Understanding UNIX permissions and chmod

Introduction

This is a topic that has been beaten to death both in books and on-line. For some reason, it seems that it is one of the most common misunderstandings that people have to face when learning how to write and/or configure their first cgi programs. This tutorial aims to clarify the concepts involved. Note that we will be referring to UNIX in a generic sense in this article. Most of what we are going to discuss here applies to all UNIX flavours. (such as Linux, SVR4, BSD etc.) It is also a good idea to type man chmod to check for the specific details on your system, too.

Users

A UNIX system serves many users. Users are an abstraction that denotes a logical entity for assignment of ownership and operation privileges over the system. A user may correspond to a real-world person, but also a type of system operation. So, in my system, I have user 'nick' that corresponds to me, but I also have user 'www' which corresponds to the privileges necessary to operate the local webserver. UNIX doesn't care about what the user means for me. It just knows what belongs to any given user and what each user is allowed to do with any given thing (file, program, device, etc) on the system. UNIX identifies each user by a User ID (UID) and the username (or login) such as 'nick' and 'www' is just an alias to the UID that makes humans more comfortable.

Groups

Users can be organized in groups. A user may belong to one or more groups of users. The concept of groups serves the purpose of assigning sets of privileges for a given resource and sharing them among many users that need to have them. (perhaps because they are all members of a project working team and they all need access to some common project files) So, on my system user 'nick' and user 'www' both belong to the group 'perlfect'. This way, they can have some shared privileges over the files for this site. User 'nick' needs them to edit the site, and user 'www' needs them to manage the webserver that will be publishing the site.

Ownership

Every file in UNIX has an owner user and an owner group. So, for any file in the system, user 'nick' may have one of the following ownership relations:

nick owns the file, i.e. the file's owner is 'nick'.
nick is a member of the group that owns the file, i.e. the file's owner group is 'perlfect'.
nick is neither the owner, nor belonging to the group that owns the file

Permissions

Every file on the system has associated with it a set of permissions. Permissions tell UNIX what can be done with that file and by whom. There are three things you can (or can't) do with a given file:

read it,
write (modify) it and
execute it.

Unix permissions specify which of the above operations can be performed for any ownership relation with respect to the file. In simpler terms, what can the owner do, what can the owner group do, and what can everybody else do with the file. For any given ownership relation, we need three bits to specify access permissions: the first to denote read (r) access, the second to denote (w) access and the third to denote execute (x) access. We have three ownership relations: 'owner', 'group' and 'all' so we need a triplet for each, resulting in nine bits. Each bit can be set or clear. (not set) We mark a set bit by it's corresponding operation letter (r, w or x) and a clear bit by a dash (-) and put them all on a row. An example might be rwxr-xr-x.What this means is that the owner can do anything with the file, but group owners and the rest of the world can only read or execute it. Usually in UNIX there is also another bit that precedes this 9-bit pattern. You do not need to know about it, at least for the time being.

So if you try ls -l on the command prompt you will get something like the following:

[nick@thekla src]$ ls -l
-rwxr-xr-x   1 nick     users          382 Jan 19 11:49 bscoped.pl
drwxr-xr-x   3 nick     users         1024 Jan 19 11:19 lib/
-rwxr-xr-x   1 nick     users         1874 Jan 19 10:23 socktest.pl

The first column here shows the permission bit pattern for each file. The third column shows the owner, and the fourth column shows the owner group. By the time, the information provided by ls -l should be enough for you to figure out what each user of the system can do with any of the files in the directory.

Directories

Another interesting thing to note is that lib/ which is a directory has permissions, too. Permissions take a different meaning for directories. Here's what they mean:

read determines if a user can view the directory's contents, i.e. do ls in it.
write determines if a user can create new files or delete file in the directory. (Note here that this essentially means that a user with write access toa directory can delete files in the directory even if he/she doesn't have write permissions for the file! So be careful with this.)
execute determines if the user can cd into the directory.

`chmod`

To set/modify a file's permissions you need to use the chmod program. Of course, only the owner of a file may use chmod to alter a file's permissions. chmod has the following syntax: chmod [options] mode file(s)

The 'mode' part specifies the new permissions for the file(s) that follow as arguments. A mode specifies which user's permissions should be changed, and afterwards which access types should be changed. Let's say for example: chmod a-x socktest.pl This means that the execute bit should be cleared (-) for all users. (owner, group and the rest of the world) The permissions start with a letter specifying what users should be affected by the change, this might be any of the following:

u the owner user
g the owner group
o others (neither u, nor g)
a all users

This is followed by a change instruction which consists of a +(set bit) or -(clear bit) and the letter corresponding to the bit that should be changed.

Let's see some examples:

$ ls -l socktest.pl 
-rwxr-xr-x   1 nick     users         1874 Jan 19 10:23 socktest.pl*

$ chmod a-x socktest.pl 
$ ls -l socktest.pl 
-rw-r--r--   1 nick     users         1874 Jan 19 10:23 socktest.pl

$ chmod g+w socktest.pl 
$ ls -l socktest.pl 
-rw-rw-r--   1 nick     users         1874 Jan 19 10:23 socktest.pl

$ chmod ug+x socktest.pl 
$ ls -l socktest.pl 
-rwxrwxr--   1 nick     users         1874 Jan 19 10:23 socktest.pl*

$ chmod ug-wx socktest.pl 
$ ls -l socktest.pl 
-r--r--r--   1 nick     users         1874 Jan 19 10:23 socktest.pl

Strange numbers...

You might have encountered things like chmod 755 somefile and of course you will be wondering what this is. The thing is, that you can change the entire permission pattern of a file in one go using one number like the one in this example. Every mode has a corresponding code number, and as we shall see there is a very simple way to figure out what number corresponds to any mode.

Every one of the three digits on the mode number corresponds to one of the three permission triplets. (u, g and o) Every permission bit in a triplet corresponds to a value: 4 for r, 2 for w, 1 for x. If the permission bit you add this value to the number of the permission triplet. If it is cleared, then you add nothing. (Some of you might notice that in fact, the number for a triplet is the octal value corresponding to the three-bit pattern - if you don't know what an octal value is, it doesn't really matter, just follow the intstructions) So if a file has rwxr-xr-x permissions we do the following calculation:

Triplet for u: rwx => 4 + 2 + 1 = 7
Triplet for g: r-x => 4 + 0 + 1 = 5
Tripler for o: r-x => 4 + 0 + 1 = 5
Which makes : 755

So, 755 is a terse way to say 'I don't mind if other people read or run this file, but only I should be able to modify it' and 777 means 'everyone has full access to this file'

Comments


Gopi	Posted at 12:47am on Monday, March 5th, 2007
what about the "s"
Ravi	Posted at 1:55am on Monday, March 26th, 2007
Nice description...Really helpful...
test	Posted at 1:38am on Thursday, April 19th, 2007
test
Ninad	Posted at 4:12am on Thursday, April 19th, 2007
Good Post :)
Anonymous	Posted at 4:47am on Tuesday, April 24th, 2007
Good Description for Chmod command
balu	Posted at 5:06pm on Tuesday, May 8th, 2007
well! i want to be a gud unix programmer although i m a electronics engineer. But i am a new unix user..found this page very helpful
Anonymous	Posted at 6:52pm on Saturday, May 12th, 2007
thanx a bunch. This is about the simplest quickest tut on chmod i've seen yet.
Roger Graham	Posted at 4:46am on Sunday, May 13th, 2007
I've always never bothered to look into unix permissioning (and just done a 777 instead of actually understanding what's going on behind the scenes). Thanks for writing such a clear concise tutorial which has cleared things up!! ;-)
neil	Posted at 3:50am on Sunday, June 3rd, 2007
very simple an quick thanks
ace	Posted at 12:33pm on Monday, June 4th, 2007
Hi at the command prompt, I am only able to view directories. when I try to change permissions, i get 'permission denied' eventhough I am the owner and no-one else has access to my computer. No matter what command I put in, i get 'permission denied'. please help as i have run out of ideas. thanks ace
suraj	Posted at 12:06am on Tuesday, June 5th, 2007
in proc file system, what 'p' flag specifies?
waste..	Posted at 12:09am on Tuesday, June 5th, 2007
ace, are you logged in as root? can you paste o/p of #whoami #ls -l #df -k
waste..	Posted at 12:15am on Tuesday, June 5th, 2007
Suraj, p : named pipe use by system In computing, a named pipe (also FIFO for its behaviour) is an extension to the traditional pipe concept on Unix and Unix-like systems, and is one of the methods of inter-process communication. The concept is also found in Microsoft Windows, although the semantics differ substantially. A traditional pipe is "unnamed" because it exists anonymously and persists only for as long as the process is running. A named
Ruth	Posted at 6:58am on Tuesday, June 12th, 2007
This is very useful. I have installed Tomcat and set User variables in .cshrc file. and when I type $CATALINA_HOME I am getting error /home/tomcat: Permission Denied. I think it is Directory permissions problem. Help please...
sm	Posted at 3:59pm on Wednesday, June 13th, 2007
Thanks very help -sm
wae	Posted at 3:57pm on Saturday, June 16th, 2007
Fantastic tutorial. Much clearer than the man page.
irina	Posted at 1:55am on Wednesday, June 27th, 2007
really useful
vks	Posted at 2:34am on Monday, July 2nd, 2007
Its really very useful.. I was also unaware about chmod XXX. But after reading this tutorial, got the concept behind. Thanks !
ak	Posted at 9:40pm on Monday, July 2nd, 2007
good one.. appreciate thinks like this in future too..
Deii	Posted at 2:48am on Wednesday, July 4th, 2007
1 question> I notice the "" suffixed at the end of the filename for certain ls command lines - the first and the penultimate line; Can shed some light on that?? [i.e. filename.pl as opposed to filename.pl]
shankar	Posted at 11:34pm on Wednesday, July 4th, 2007
I want to delete a file of a different owner. What permission should that different owner can give while creating that file to do the same?
shankar	Posted at 12:08am on Thursday, July 5th, 2007
Just by giving "rwx" permissions to all users at the folder level. I am novice to unix. Thanks, if anybody made a try.
Murtaza	Posted at 12:07pm on Saturday, July 14th, 2007
@Roger Graham - using 777 without understanding it, is really stupid, anyways glad this post has you thinking again. LOL. Sorry offense meant...
Shyam	Posted at 10:19pm on Thursday, August 16th, 2007
It `s really helpful
Shyam	Posted at 10:19pm on Thursday, August 16th, 2007
Good one
NP	Posted at 7:36am on Wednesday, August 22nd, 2007
@Murtaza - nobody likes a smart arse!
Naveen Kanakam	Posted at 11:19am on Friday, September 14th, 2007
Thanks for help..Its really great...
Sandy	Posted at 11:38pm on Monday, September 17th, 2007
OK cool Nice info i will delete few files now
asif	Posted at 4:59am on Tuesday, September 25th, 2007
nice one !
sriram	Posted at 6:38am on Tuesday, September 25th, 2007
is there any other command to change the attributes(using c)
Hariharan	Posted at 3:36am on Wednesday, October 3rd, 2007
Best one
Nilesh	Posted at 2:08pm on Saturday, October 6th, 2007
Nice, cleared some stuff up - thanks!
Dhawal	Posted at 4:22am on Thursday, October 11th, 2007
Great! The example cleared my doubts completely
raj	Posted at 10:41pm on Monday, October 15th, 2007
yes 777 is used to be the way to go for me. But now i clearly understand. Thanks for making my day
rsom	Posted at 6:04am on Tuesday, October 16th, 2007
What does the 'c' permission define for permissions, 'crw-rw-rw-'?
pete	Posted at 7:40am on Sunday, October 21st, 2007
in reply to rsom: 'c' represents a character device e.g. a serial port or a terminal - note these process data in bits. 'b' represents a block device e.g. hard drive, cdrom etc.. these process data in blocks or bytes. 'l' represents a symbolic (soft) link as in a Windows shortcut 'd' represents directory '-' represents a file
Daniel	Posted at 11:12am on Sunday, October 21st, 2007
Nice Description.. it really help me..
Mikael	Posted at 7:58pm on Friday, November 2nd, 2007
I always use 4 2 1 and just add the numbers, makes more sense for me :-) 4 2 1 read write execute and "user group world" is all you need to put into memory!
Eben	Posted at 7:55am on Monday, November 5th, 2007
This relevant manual has cleared my previous misunderstanding about chmod. This is good
imkat	Posted at 3:02pm on Tuesday, November 6th, 2007
rili helpful. thanks...
Ravi	Posted at 8:36pm on Tuesday, November 6th, 2007
Simple and easy ...very good
Ben	Posted at 12:19pm on Wednesday, November 7th, 2007
What does the 'p' mean prwxr-xr-x? Thx
Aps	Posted at 6:37pm on Monday, November 12th, 2007
Hi everyone It's my first time to use unix and I am having problem. I know that I logged in as root, because when I type pwd the output is "/" ( which I know is the root). Upon logging in this was the message I've got: "/etc/profile[145]: /home/alc10513: not found". Also I cannot modify a file nor make a directory. Please help me. Thanks.
Aidan	Posted at 7:00am on Tuesday, November 20th, 2007
@Aps There are two kinds of root in unix, root user and the root of the filesystem. pwd prints the current working directory (which in your case is the root of the filesystem), it doesn't tell you who you are logged in as. To find that out, type whoami. To become root user, type sudo -s (you will need to know root's password). If you have no home directory and you can't make a file/directory, it sounds like your user account was not setup properly. You can make a new user by becoming root (sudo -s) then typing adduser yourname (replace yourname with whatever name you want). Type man adduser for more information.
Hasan Mehmood	Posted at 11:27pm on Wednesday, November 28th, 2007
though the topic was not complex but the way you have described the chmod command make it soooooooo easy to understand. please let me know if you have written any book on Linx/Unix. hasandirect@yahoo.com
Elle	Posted at 4:00pm on Friday, December 7th, 2007
does anyone know how to remove the set bit from a file. For example, I want the file permissions changed form -rw-rw-r--+ to -rw-rw-r--
TPot	Posted at 8:00pm on Tuesday, December 11th, 2007
To quote the man page on AIX (which says it better than I can): The mode displayed with the -e flag is the same as with the -l flag, except for the addition of an 11th character interpreted as follows: + Indicates a file has extended security information. For example, the file may have extended ACL, TCB, or TP attributes in the mode. The access control information (ACL) of a file is displayed by using the aclget command. Try the acledit command.
Jasleen	Posted at 8:36am on Thursday, December 20th, 2007
hey, thanks it was really a great help
KMK _TESTER	Posted at 7:58am on Friday, January 11th, 2008
Nice tutorial Was really useful for me in real time testing
Travler	Posted at 9:42am on Wednesday, January 23rd, 2008
HUH? :)
Jim	Posted at 12:15pm on Wednesday, February 6th, 2008
The question I have that this and everything else I've seen on the web talks right past is "in terms of web hosting, how does a server know if I am the owner or not when using a php (or other script) to upload a file or anything else requiring permissions?" IF that could be answered in 500 words or less, that would make this a great tutorial.
Abdullah	Posted at 7:52am on Tuesday, February 12th, 2008
This is a great page! - I'm impressed.
Abhijit	Posted at 3:05am on Friday, February 22nd, 2008
Really nice explanation of chmod command in unix. This will definitely help me in my new project wgich is 50% based on Unix env.
Cindy	Posted at 5:58am on Friday, February 22nd, 2008
What does the "t" in the following permission setting stand for: drwxrwxrwt I'm confused :o(
nico	Posted at 2:24pm on Wednesday, February 27th, 2008
Cindy, concerning the 't' which is sticky bit I just found this at linuxforums: If you have a look at the /tmp permissions, in most GNU/Linux distributions, you'll see the following: clem@pluto:/$ ls -l \| grep tmp drwxrwxrwt 10 root root 4096 2006-03-10 12:40 tmp The "t" in the end of the permissions is called the "sticky bit". It replaces the "x" and indicates that in this directory, files can only be deleted by their owners, the owner of the directory or the root superuser. This way, it is not enough for a user to have write permission on /tmp, he also needs to be the owner of the file to be able to delete it. In order to set or to remove the sticky bit, use the following commands: chmod +t tmp chmod -t tmp The url to the article: http://www.linuxforums.org/security/file_permissions.html
asifraheman	Posted at 11:05pm on Thursday, March 27th, 2008
Really nice explanation of chmod command in unix. This will definitely help me in my new project wgich is 50% based on Unix env.
Anonymous	Posted at 5:52am on Monday, April 7th, 2008
Its really very nice and helpful for any beginner. It gives me not only syntax idea but also detail impelementation knowledge. Site like this are very much helpful. Thanks Mohammed Tahir Khanooni
gyanendra verma	Posted at 1:33pm on Thursday, April 17th, 2008
I have created a script and for user i do not have execute permission. it is -rw-r--r-- still i am able to execute the script. what could be the reason
Addagirl	Posted at 8:40pm on Monday, April 21st, 2008
I am installing an autoresponder and need to create a htaccess file and set the following permissions: chmod for ar.cgi to 755 chmod for config.cgi to 755 chmod for activate.cgi to 755 chmod for lite.pm to 644 chmod for the autoresponder folder to 775. I do not know how to set this up or the proper format it sould be written in so I can upload it as an htaccess file on my web server. Can anyone help?
John	Posted at 5:53am on Tuesday, May 6th, 2008
Really nice explanation of chmod command in unix.very useful.
Gowtham	Posted at 3:25pm on Thursday, May 22nd, 2008
HI, I am having some problem with permissions. In this document, I couldnot able to find it out. My scenario is like this. I am having a user "nick"(home path - /home/nick) and user "stick" (home path - /home/stick). I am having a folder folder1 in nick folder. And I want to move that folder to Stick folder. Even though I have 777 permission to all the files for folder1 and its subfolders , I am not able to move the folder to Stick home path. Please let me know your coments. If it is possible , please post the reply to sen_smarty@yahoo.co.in
indrajeet	Posted at 8:28pm on Thursday, May 22nd, 2008
really use ful i having the problem with the permissions i want answer if possible please send me on sonud6208@gmail.com
Raja	Posted at 1:53am on Monday, May 26th, 2008
Nice tutorial...
Prosenjit	Posted at 2:46am on Tuesday, May 27th, 2008
good enough...
Neeraj	Posted at 2:06pm on Friday, May 30th, 2008
Nice info , explained quiet beautifully.
Visakh	Posted at 1:49am on Friday, June 6th, 2008
Very helpul. It is easy to understand. Thanks :)
Sanjeev	Posted at 5:36am on Tuesday, June 17th, 2008
Very well explained, easy to understand basics of permission and chmod command
Jenny	Posted at 5:48am on Wednesday, June 18th, 2008
nice work.i now understand the concept of chmod though i just started learning UNIX.wud want more materials on UNIX
Amit	Posted at 2:29am on Monday, June 23rd, 2008
thanks a lot for such a wonderful information....
James	Posted at 6:00am on Wednesday, June 25th, 2008
Web TemplatesIt is really impressive work. Nice work man keep it up.
Rick	Posted at 6:02am on Wednesday, June 25th, 2008
http://www.5050webs.com...Good online source to get information about Unix..
Chendhil	Posted at 12:58am on Monday, July 7th, 2008
Good and easy to understand. Thanks..!
michael	Posted at 10:00pm on Thursday, July 10th, 2008
Yes. Very good. Suggestion to sharpen up the part on ownership. Ownership Every file in UNIX has an owner user and an owner group. So, for any file in the system, user 'nick' _has exactly_ one of the following ownership relations: * nick owns the file, i.e. the file's owner is 'nick'. * nick _does not own the filem but_ is a member of the group that owns the file, i.e. the file's owner group is 'perlfect'. * nick is neither the owner, nor belonging to the group that owns the file (The reason this is significant is because permissions are evaluated only for the particular relation - there is no conjunction going on. For example, if a user is both the owner, and a member of the group that owns the file, but permission is r--rwx--- then the user will not have permission to execute the file.)
Sys Admin pk	Posted at 3:12am on Friday, July 11th, 2008
this is great information for beginners.......please continue such information sharing
KalarioS	Posted at 2:35am on Friday, July 18th, 2008
Nice article .... explains the chmod in simple english
Dinesh	Posted at 8:40pm on Saturday, July 19th, 2008
what about the "s" here drwxr-s--- ? how to give "S" permision to new file ?
Parveez Khan	Posted at 10:44pm on Monday, July 21st, 2008
Thanks a lot.....
Divya	Posted at 2:13am on Monday, July 28th, 2008
Thanx for such a nice explanation for chmod.
Divya	Posted at 2:15am on Monday, July 28th, 2008
is there any thing called chmod a=x? what is the use of =?
barking squirrel	Posted at 5:39pm on Sunday, August 24th, 2008
Gotta respect an author who begins an article by putting down their reader; "For some reason, it seems that it is one of the most common misunderstandings that people have ..." So what does the 's' mean?
Drive by	Posted at 9:22am on Thursday, August 28th, 2008
s in the place where 'x' would normally go is called the set-UID or set-groupID flag.
Drive by	Posted at 10:07am on Thursday, August 28th, 2008
The set user ID, setuid, or SUID permission. When a file for which this permission has been set is executed, the resulting process will assume the effective user ID given to the user class.
Anonymous	Posted at 10:09am on Thursday, August 28th, 2008
Unless you are talking about the first character... The first character indicates the file type: - denotes a regular file d denotes a directory b denotes a block special file c denotes a character special file l denotes a symbolic link p denotes a named pipe s denotes a domain socket
Sush	Posted at 4:01am on Friday, August 29th, 2008
Hi frenz.Could any1 help me out why doesnt chmod +w filename doesnt reflect in the write permission field for all.I mean for user,group and others.I m confused !!! Please Help Me !!! Thanks Lads !!!
Karthick	Posted at 12:14am on Wednesday, September 10th, 2008
Useful
Karthick	Posted at 12:20am on Wednesday, September 10th, 2008
Hi Sush.While using chmod command you should specify to whom you are setting write permission.Check with this one chmod ugo+w ..
Mansvi	Posted at 10:16pm on Tuesday, October 7th, 2008
"Drive by Posted at 10:07am on Thursday, August 28th, 2008 The set user ID, setuid, or SUID permission. When a file for which this permission has been set is executed, the resulting process will assume the effective user ID given to the user class. " Can you please elaborate it further ..?
robertsb	Posted at 9:50am on Monday, November 17th, 2008
nice post, simplified things a bit. thx
....	Posted at 1:09pm on Tuesday, November 18th, 2008
Meep Meep
Kalai	Posted at 7:40am on Tuesday, December 2nd, 2008
Hi, Though I am "auser" the owner of the directory, i'm not able to write/create a file under that directory. >ls -ld /MEC/reports drwxr-xr-x 88 auser emc 4096 Dec 2 13:30 /MEC/reports >touch /MEC/reports/testfile touch: creating `testfile': Read-only file system This was my error. Help me out plz.
kishore	Posted at 2:22am on Wednesday, December 3rd, 2008
this is very usefull document.
Pydi	Posted at 2:07pm on Wednesday, December 3rd, 2008
Good .... Still there is a gap for an examples.. Thank you!!!!!!!
Anonymous	Posted at 11:24pm on Tuesday, January 6th, 2009
Gud One..very descriptive ..... Srinivas.M
Srinivas.M	Posted at 11:25pm on Tuesday, January 6th, 2009
Gud One..very descriptive .....
Anonymous	Posted at 8:50am on Saturday, January 31st, 2009
marvoloeus discription
Robert	Posted at 9:26am on Tuesday, February 24th, 2009
its great it helped a lot.visit Effective Resume for making a great unix administrator resume.
sid	Posted at 11:09pm on Sunday, March 1st, 2009
thanks man, i'm glad that there's an alternative to professors out on the internet
Amit Pawar	Posted at 6:23am on Monday, March 2nd, 2009
A Perfect Description........ Thanks a lot.
Simon	Posted at 1:37pm on Tuesday, March 3rd, 2009
Someone help: which command can I use to Make the permissions so only I can read/write permissions. Everyone else is read only.
Nitin	Posted at 9:35am on Friday, March 6th, 2009
Hey .. How do i know what permission is there on a file ? Eg : file_a has 755. so, what_command file_a sud give me back 755 ?
John P	Posted at 12:56pm on Wednesday, March 11th, 2009
I just failed a Unix test at work.. They gave us 12 things to do in UNIX and I failed.. I had to become "root" and change the permissions... Im bummed out... :-( Any good books out there on UNIX or websites??? I need all the help i can get...
mogwai	Posted at 10:14am on Friday, March 13th, 2009
4 read 2 write 1 execute 4+1=5 or read and execute which is whats needed to list a directory. chmod -R 755 /path/dirname will change all files within the directory to read and execute. that covers all you need to know about chmod.
George	Posted at 11:13pm on Thursday, April 2nd, 2009
I am working on a shell script which needs to get the permission of a file.My requirement is: Check the permission on a particular file. If the file is read only , then exit else edit it.... Now the problem is I need the permission on a file(only the permisson and not other details) in a variable. Can anybody help me? Thanks in advance
Senthil	Posted at 2:03am on Saturday, April 4th, 2009
Nice Hint
Niraj	Posted at 10:56am on Saturday, April 4th, 2009
Brief and nice description
susanne	Posted at 8:39pm on Thursday, April 16th, 2009
Thanks for the info. I've been asked for the 'autoresponder folder - which I can't find. However, if people are still asking the question - "This is a topic that has been beaten to death both in books and on-line" - then this answer doesn't help!!! You still haven't answered the question in 'newbie-speak'- and yes, we newbies are informed enought to even understand the terms ... oh well ... Thanks for the info I did get. Susanne sf7272@iinet.net.au
sud	Posted at 7:05am on Sunday, April 26th, 2009
this worked a lot for me.. thanks...
vinod kumar	Posted at 4:31am on Wednesday, May 6th, 2009
Really it's good and clear to understand.
CNN	Posted at 4:34am on Wednesday, May 6th, 2009
Hi, It is very interesting and clear,such a nice explanation. Thanks, Naren
vinx	Posted at 11:23pm on Sunday, May 10th, 2009
good work..thanks
Stuart Hendry	Posted at 12:31pm on Friday, May 29th, 2009
Cool, very informative, thanks
Tony	Posted at 8:53am on Monday, June 1st, 2009
This was very helpful Thanks
kamal	Posted at 8:17pm on Wednesday, July 22nd, 2009
thank.. now I undestand....
Ravi	Posted at 2:33am on Thursday, July 30th, 2009
-r-sr-x--- what does "s" means here
Ravi	Posted at 2:34am on Thursday, July 30th, 2009
-r-sr-x--- what does "s" means here
Ravi	Posted at 2:34am on Thursday, July 30th, 2009
-r-sr-x--- what does "s" means here
laxmikant	Posted at 11:25pm on Wednesday, August 19th, 2009
s in above is for user id...suppose there are two files..File one is accesible to only one i.e owner & File two is accessible to everyone..if someone who is not owner of files wants to access file two then that is available..but problem here is that if file two want some data from file one which is not possible since file one has access to only owner. This problem can solved by setting user id for file two without changing permission of file one ..chmod u+s filetwo..and this has to be done by owner of files...By this option anyone accessing file two,is considered as owner..temporarily ..and pemission is granted to read file one ...u can not access file one directly ..u have to go through file two.
J.R.	Posted at 5:13pm on Monday, August 24th, 2009
Nice, thanks.
Pradeep	Posted at 3:09am on Tuesday, August 25th, 2009
Thanks .. Nicely explained
Devika	Posted at 3:35am on Friday, September 4th, 2009
Thanks A Lot! very informative
Martin	Posted at 8:03pm on Saturday, October 24th, 2009
Very helpful, thanks.
m.noman	Posted at 12:33pm on Monday, October 26th, 2009
how im shutdown sco open server unix shutdown any use"r account without enter in root?
Rno	Posted at 10:58am on Wednesday, November 4th, 2009
Excellent
priyanka	Posted at 8:27pm on Tuesday, November 17th, 2009
intresting!!!!
Amarjit	Posted at 11:50pm on Friday, November 27th, 2009
Very nice topic. Very useful. Require more for other commanfd.
Abhisek	Posted at 9:11pm on Monday, December 14th, 2009
Excellent. Just what I was looking for...
Anirban dutta choudhury	Posted at 8:52am on Tuesday, December 15th, 2009
Hey this is good stuff, I like the content and also the way its presented.
Kumar.R	Posted at 2:39am on Tuesday, December 29th, 2009
Description is very useful and understandable..
Pavan	Posted at 2:03am on Thursday, January 7th, 2010
it's good.very helpful.
ashutosh	Posted at 1:39am on Tuesday, January 12th, 2010
nice one..
Balasaraswathi	Posted at 10:15pm on Tuesday, January 19th, 2010
document is understandable
vera	Posted at 1:15pm on Thursday, January 21st, 2010
Thank you. Now I understand.
Vish	Posted at 5:36am on Sunday, January 24th, 2010
Gud One.. Very Helpful...
hi	Posted at 12:30am on Friday, January 29th, 2010
this is good i wnat some clarrification abt awk and sed...
hi	Posted at 12:30am on Friday, January 29th, 2010
this is good i wnat some clarrification abt awk and sed...
Santosh	Posted at 5:44am on Friday, February 5th, 2010
Very good description, kept it simple and to the point. It was very helpful. thank you
chitransh	Posted at 2:46am on Monday, February 8th, 2010
Why a new file get 666 permisions???where goes 111 ?????
chitransh	Posted at 2:50am on Monday, February 8th, 2010
Why a new file get 666 permisions???where goes 111 ?????
dim	Posted at 3:28am on Wednesday, February 17th, 2010
Thanks, helped me out!
vijaya	Posted at 12:54pm on Wednesday, February 17th, 2010
rwx for read, write, execute but above -rwxr-xr-x what that extra r is for
Lucina	Posted at 9:50am on Thursday, February 18th, 2010
Super articulate - thank you so very much!
ashwini	Posted at 5:16am on Monday, March 1st, 2010
good discription.
vel	Posted at 1:15pm on Thursday, March 4th, 2010
Good Example..
Battu	Posted at 10:55pm on Thursday, March 4th, 2010
Awesome buddy. Great job.. keep it up.. :-). Let me know where will i get this kind of information for all related to unix stuff..! wish to learn unix completely
Battu	Posted at 10:57pm on Thursday, March 4th, 2010
Awesome buddy. Great job.. keep it up.. :-). Let me know where will i get this kind of information for all related to unix stuff..!
Rick	Posted at 7:11am on Wednesday, March 10th, 2010
Excellent explanation. I've read many, but this one finally made sense. Thank you!
Anonymous	Posted at 11:25pm on Monday, March 22nd, 2010
nice but stii i have a problem because i am a new user of unix
metabolic diet	Posted at 8:19am on Friday, March 26th, 2010
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Prashanthini R	Posted at 11:51pm on Monday, March 29th, 2010
Really informativa and easy to understand
ray	Posted at 3:49pm on Thursday, April 22nd, 2010
thank you so much !
Pradeep	Posted at 7:57am on Friday, April 23rd, 2010
Hi all , Please do reply for this issue > Query 1 : I wanna give (rw access for Team Lead) and (ro access for the Team members) "who all belong to a same group" , and the condition is i shouldn't use chmod command or a GUI , how to set the permissions ?? Query 2: What is the port number for TCP ?? Please do reply these to my email id : pradeep.kayprady@gmail.com
BURCHMaricela35	Posted at 8:48pm on Monday, April 26th, 2010
This is good that we are able to get the lowest-rate-loans.com and this opens up new opportunities.
orub	Posted at 9:30pm on Wednesday, April 28th, 2010
thanks very much, very helpfull.
Vladimir	Posted at 12:05pm on Thursday, May 6th, 2010
Nice, thank you for good explanation
rakesh	Posted at 5:37am on Saturday, May 8th, 2010
Many many thanks and regards to the author of this article. This article is really very helpful,nice and excellent. I really appreciate this article for its simple explainatio of tough and confuzing concepts of unix. regards Rakesh
Pieter Verb	Posted at 9:49am on Monday, May 10th, 2010
What if I want to change only the folder permissions to executable, and not the files? chmod -R u+x * This changes the files to executables too.
Arun S Kumar	Posted at 2:07am on Thursday, May 13th, 2010
Thanks for the help
DRB	Posted at 8:16am on Monday, May 17th, 2010
@Pieter Verb Had the same question and I think I have figured it out -- someone please correct if this is not the best way -- it worked for me: chmod 755 */
Lokesh	Posted at 7:29am on Wednesday, June 2nd, 2010
quite helpful!
Dev	Posted at 6:07am on Thursday, June 3rd, 2010
Very Easy to understand and useful as well
mugi	Posted at 10:52pm on Wednesday, June 23rd, 2010
this is what i have been looking for
AbuiEyiJean	Posted at 4:39am on Thursday, July 1st, 2010
Simple and helpful description. Many Thanks!
vineet chaudhary	Posted at 2:05am on Tuesday, July 6th, 2010
thanks for providing such a user friendly tutorial.....
manoj singh	Posted at 10:25pm on Wednesday, July 28th, 2010
I have create a user but i am not allow anothe user login my server my server login only root user ,how can check security for my server.
scorpio	Posted at 12:17am on Thursday, August 5th, 2010
Very good explanation! Thank you.
varun	Posted at 4:46am on Monday, August 9th, 2010
gud 1.. really helpfull... thanks
Harsh	Posted at 7:02am on Tuesday, August 10th, 2010
good work...........
nagaraju	Posted at 3:24am on Friday, August 20th, 2010
excellent
umair	Posted at 5:07am on Thursday, September 9th, 2010
By far the BEST tutorial on permissions on the internet. -cheers.
g.sudhakar	Posted at 6:19am on Friday, September 17th, 2010
it is not cleare information ,in this file system Permissions mainly three commands ls,chmod,other so chang information
vikram	Posted at 6:36pm on Friday, September 17th, 2010
i liked it very much
Charles	Posted at 4:33am on Wednesday, September 29th, 2010
@Pieter Verb and @DRB You Need To Change The Permissions on a Folder and Not on The Files Inside it. the R attribute "chmod -R" is recursive, so the command changes the permissions of all the files and folders inside the destination, omit this attribute and it will Work ! Pretty Good Tutorial, Thank You and Keep up The Good Work
doubt	Posted at 5:07am on Wednesday, September 29th, 2010
its helpfull, tq
test	Posted at 11:54am on Thursday, September 30th, 2010
Gives idea on permission..thanks dude.
surendra	Posted at 9:54pm on Thursday, October 21st, 2010
It was really helpful .Thanks for uploading this content
Prashant	Posted at 2:06am on Friday, October 22nd, 2010
Really nice to understand
mahir azad	Posted at 1:41am on Thursday, October 28th, 2010
good details
mahir azad	Posted at 1:43am on Thursday, October 28th, 2010
good details
shivapriya	Posted at 11:18pm on Thursday, October 28th, 2010
very helpfull. i have doubt in a shell script . ${ADW_HOME}/env/izmst.env why there is a dot(.) before $ sign? what is the meaning of this statement?
shivapriya	Posted at 11:20pm on Thursday, October 28th, 2010
very helpfull. i have doubt in a shell script . ${ADW_HOME}/env/izmst.env why there is a dot(.) before $ sign? what is the meaning of this statement?
Pavan	Posted at 5:16am on Friday, October 29th, 2010
gud explaination
Rahul	Posted at 1:17am on Tuesday, November 9th, 2010
thanks
Vikas saini	Posted at 10:02pm on Monday, November 15th, 2010
Really great way of description thanks yaar
hs	Posted at 10:25pm on Thursday, November 18th, 2010
its not working
Ma Diga	Posted at 10:30pm on Saturday, November 27th, 2010
Good job. I like articles that are basic and easy to understand. - More Linux Articles
Anonymous	Posted at 8:09am on Monday, November 29th, 2010
I have a worldbook westerndigital powerbook wifi'd to three computers that use it for storage AND I work off the worldbook (not my computers). What setting to I put for permissions so everyone at every computer can access, read, write, execute (including save) from and to the worldbook? I see Everyone, System and Unix use root and unix group root thing. If I have a chimod I don't know what it is or where it is or what it has to do with my question. I JUST want to know what and how to set my permissions on this worldbook thing. THanks _ Not a techie like you people. YOu can send the answer to nancy4366@hotmail.com. YES I read this article. NO, I did not understand it because I'm not computer savy like you people. Sorry. THanks for reading this. I hope someone can just tell me what to do.
Hypnogal	Posted at 8:09am on Monday, November 29th, 2010
I have a worldbook westerndigital powerbook wifi'd to three computers that use it for storage AND I work off the worldbook (not my computers). What setting to I put for permissions so everyone at every computer can access, read, write, execute (including save) from and to the worldbook? I see Everyone, System and Unix use root and unix group root thing. If I have a chimod I don't know what it is or where it is or what it has to do with my question. I JUST want to know what and how to set my permissions on this worldbook thing. THanks _ Not a techie like you people. YOu can send the answer to nancy4366@hotmail.com. YES I read this article. NO, I did not understand it because I'm not computer savy like you people. Sorry. THanks for reading this. I hope someone can just tell me what to do.
Anonymous	Posted at 2:49pm on Monday, November 29th, 2010
so comprehensive style in explanation. Now, it has become clear a to z of the command. Mahin
Anonymous	Posted at 4:08pm on Monday, November 29th, 2010
Thank you very much. Felt like learned some stuff in UNIX.
siva	Posted at 12:22am on Thursday, December 9th, 2010
simple and nice...
siva	Posted at 12:23am on Thursday, December 9th, 2010
simple and nice...
Laxmikant	Posted at 2:00am on Friday, December 17th, 2010
Few more examples can be added. e.g. the file permissions change for particular user.
Laxmikant	Posted at 2:00am on Friday, December 17th, 2010
Few more examples can be added. e.g. the file permissions change for particular user.
Rajendra	Posted at 11:32pm on Friday, December 24th, 2010
Simple to understand.. Thanks!!!
raju	Posted at 12:02am on Monday, December 27th, 2010
drwx------ 3 nick users 1024 Jan 19 11:19 xyz how to change the permession of directory
Bhaskar	Posted at 2:21am on Tuesday, December 28th, 2010
Excellent peace of information, thanks.
Gaurav	Posted at 3:20am on Tuesday, January 4th, 2011
Very usefull post
Anonymous	Posted at 11:36pm on Thursday, January 13th, 2011
hi if any one have hp-ux fundamentals PDF please send to my id gsbaikerikar@gmail.com regards Gourishankar Baikerikar
Karunakar	Posted at 2:26am on Wednesday, January 19th, 2011
Nice description with examples, very much helpful Thanks
cimi	Posted at 4:03am on Wednesday, January 19th, 2011
Very Helpful.
Gunjan	Posted at 4:16am on Friday, February 11th, 2011
I am looking at a folder which makes all the information to null. The permission is "crw-rw-rw- ". Here what "c" means..?
raghu	Posted at 2:51pm on Friday, February 11th, 2011
thanx a lot. very informative.
Ranjana	Posted at 7:36am on Sunday, February 20th, 2011
Thanks... I learnt about chmod well...
prof	Posted at 9:08am on Monday, February 21st, 2011
thanx guys this is more than useful 2 me
vikas	Posted at 4:43pm on Tuesday, February 22nd, 2011
good article
Mullaiselvan. M	Posted at 1:48am on Saturday, March 5th, 2011
Nice and Clear, Thanks a lot.
Hemant	Posted at 4:47am on Tuesday, March 8th, 2011
thanks for given a easy solution. it works successfully. Thanks........
noname	Posted at 10:31pm on Friday, March 18th, 2011
stupid chicken. your info necessary no one. i hate this is
Ros	Posted at 8:50am on Tuesday, March 22nd, 2011
Hello everybody. Wicht is the chmod to -rwsr-s---???. Many thanks. Ros
Mtresspasser	Posted at 10:58pm on Tuesday, March 29th, 2011
I work in office n i 4got my pwd in unix.my admin has assigned me a task 2 hack d pwd from /etc/pwd. how to do it?
Santosh Yadav	Posted at 12:16am on Thursday, April 14th, 2011
Incase “Irreversible encryption” applied….. Can be cracked by dictionary/bruit force utilities
blackhawk	Posted at 10:33am on Friday, April 29th, 2011
Nice Article......i never forget permissions with this explanation.thanks
Anonymous	Posted at 8:34am on Thursday, May 5th, 2011
nice description..
Satya	Posted at 8:35am on Thursday, May 5th, 2011
nice description..Novice can understand clearly..
Anonymous	Posted at 3:00pm on Monday, May 9th, 2011
very nice! well done!
Atul Ranjan Shahi	Posted at 4:25pm on Wednesday, May 25th, 2011
Its realy great!!! Thanks to help me. Keep it up.
karthick sharma	Posted at 4:50am on Wednesday, June 1st, 2011
It was really good. thankyou..!
Spence	Posted at 6:34am on Thursday, June 2nd, 2011
Quite helpful, thanks for the well written article.
vikram poojary	Posted at 9:39pm on Friday, June 24th, 2011
plz let us know how assign permission to particular user in aix
robert	Posted at 2:20am on Sunday, June 26th, 2011
in safe mode my third row is set to admin, everytime i type in my drive it says permission denied, i log in as my name, my question is i need to get my start-up window, i set my harddrive to the admin according to safe mode i want to get it back running on my name..please help
Jeeva N	Posted at 10:25pm on Sunday, June 26th, 2011
Its very use full.. I am really like it...
neil.....	Posted at 6:22am on Friday, July 1st, 2011
very simple understanding me.
Anonymous	Posted at 5:22am on Wednesday, July 6th, 2011
Very good for beginners
Alexander Nemsadze	Posted at 1:32am on Thursday, July 7th, 2011
Perfect explanations, thanks
gino The IT practitioner	Posted at 6:11pm on Thursday, July 7th, 2011
tnx for the info...
GlobalGoodGroup	Posted at 5:25pm on Thursday, July 14th, 2011
Global Good Linux admins, thank you for getting better at your craft. At GlobalGoodGroup.com we are connecting the worlds people and information and that is not possible without people keeping the worlds computers online. -Thankyou from JBois
Mandar	Posted at 7:25pm on Thursday, July 14th, 2011
great doc
Sag-e-Attar Junaid Atari	Posted at 11:49pm on Sunday, July 31st, 2011
Nice article.
Anonymous	Posted at 11:03am on Thursday, August 4th, 2011

ajay kumar	Posted at 3:25am on Friday, August 5th, 2011
Any one plz send me PDF for the same command chmod file permissions . Regards, Ajay Kumar
Evgen	Posted at 8:42am on Sunday, August 21st, 2011
Thank You for the article, it is very good and clear for beginners in Unix.
naresh	Posted at 7:46pm on Tuesday, August 30th, 2011
how to add user,group,owner..........and how to remove those
Humphrey	Posted at 5:00am on Wednesday, September 21st, 2011
Very clear! Thanks. It gave me a good description of the unix filesystem.
Hemal	Posted at 3:02am on Wednesday, September 28th, 2011
Check the file permission :There might be file permission 777 which hacker can used it to hack it again. So, you should check the file permission and then give the correct file permission as follows: All folder permissions should be set to 755 All files permissions should be set to 644 Files that you want to edit in the WordPress Theme editors permissions should be set to 666 Never ever use 777 for WordPress permissions
Hemal	Posted at 3:03am on Wednesday, September 28th, 2011
Check the file permission :There might be file permission 777 which hacker can used it to hack it again. So, you should check the file permission and then give the correct file permission as follows: All folder permissions should be set to 755 All files permissions should be set to 644 Files that you want to edit in the WordPress Theme editors permissions should be set to 666 Never ever use 777 for WordPress permissions
Anonymous	Posted at 2:33pm on Monday, October 31st, 2011
Very well described and useful.
khan	Posted at 8:58am on Thursday, November 3rd, 2011
help me finish my lab work ^^
Bacon	Posted at 9:28am on Thursday, November 24th, 2011
Top banane
AieYan	Posted at 2:14pm on Saturday, December 10th, 2011
Nice... Really Helps.. in terms of "To Do It" and "To Get It"
harsha	Posted at 1:31am on Saturday, December 17th, 2011
good information ..its easy now
Anonymous	Posted at 1:13pm on Saturday, December 31st, 2011
simple to understand and easy to learn. thank you.
Shweta	Posted at 11:35pm on Thursday, January 12th, 2012
This write up is very simple and hence very helpful ! I loved it...
Aditya	Posted at 11:16am on Friday, January 13th, 2012
Thanks for taking writing so simply, I can't explain how easy and useful this is for a starter like me.
virat	Posted at 9:23pm on Sunday, January 15th, 2012
Very Nicely Described...Easy to understand.
qbq	Posted at 5:52am on Monday, January 16th, 2012
Can you tell me what the dot means at the end? -rw-rw----. ..........^
FK	Posted at 7:50pm on Wednesday, January 25th, 2012
any one know how to check What account have 777 permission? on any server...........plz help.
FK	Posted at 7:50pm on Wednesday, January 25th, 2012
any one know how to check What account have 777 permission? on any server...........plz help.
Lakshmi	Posted at 2:10am on Thursday, February 2nd, 2012
Its simple and easy to understand the file permissions.
Anonymous	Posted at 8:33am on Thursday, February 9th, 2012
nice explanation
John	Posted at 3:15pm on Thursday, February 9th, 2012
s is the set-UID or set-groupID flag. It is used to allow a user to execute a file with the file's owner or group permissions...if you ever check back
Kevi	Posted at 11:42pm on Wednesday, February 15th, 2012
Really a valuable description......
Kevi	Posted at 11:43pm on Wednesday, February 15th, 2012
Really a valuable description......
OM PRAKASH	Posted at 7:24am on Thursday, February 23rd, 2012
IT IS REALLY VERY VERY GOOD AND HELP FULL TO KNOW THE MEANING OF CHMOD WHY AND WHEN IT WILL BE REQUIRED BY THE USER AND TAKE A GOOD RESPONCE. ABOUT IT..
alfredo	Posted at 6:21am on Monday, March 12th, 2012
mucho good tutoriale! very good
Windows Tech Support	Posted at 11:59am on Tuesday, March 13th, 2012
Great examples, really to the point! windows tech support
loeschg	Posted at 8:16pm on Saturday, March 17th, 2012
5 years running and still very relevant. Thanks for taking the time to put this together.
RANA	Posted at 7:59pm on Sunday, March 18th, 2012
so good explanation.
Asraful Sk	Posted at 8:40am on Wednesday, March 21st, 2012
Good Description for Chmod command
POTHIREDDY	Posted at 3:59am on Tuesday, March 27th, 2012
simply superb..and thanks for info:-)
soladmn	Posted at 12:21am on Tuesday, April 3rd, 2012
What does Rrw-rw---- "R" means here ?
Anonymous	Posted at 6:14am on Sunday, April 29th, 2012
Very helpful!
Jagjit	Posted at 2:41am on Sunday, May 27th, 2012
Very effective and very helpful too. Great Job done
printed tissue packs	Posted at 3:48am on Monday, May 28th, 2012
hello,this post is really wonderful....it's really very intersting and informative....keep sharing.... printed tissue packs
Anonymous	Posted at 8:38am on Saturday, June 9th, 2012
Thanks so much. this was very useful
Prashant	Posted at 5:08am on Monday, June 11th, 2012
Nice description
Preethi	Posted at 6:46am on Monday, June 11th, 2012
Quick Reference
veni	Posted at 8:14am on Monday, June 18th, 2012
Very nice thanks
Good One	Posted at 12:31am on Wednesday, July 4th, 2012
A detailed explanation on chmod! Thanks for that.
vinee	Posted at 10:02pm on Thursday, July 12th, 2012
good one
mike	Posted at 9:17am on Sunday, July 15th, 2012
Thanks for making this clear. Much appreciated!
Anuj	Posted at 11:20pm on Wednesday, July 18th, 2012
Very good article...
Anonymous	Posted at 2:18am on Thursday, July 19th, 2012
Thanks
Praveen	Posted at 7:01pm on Tuesday, July 24th, 2012
what is u007 means ?
richard	Posted at 2:49am on Monday, July 30th, 2012
75%, but what about the rest.
wolf	Posted at 11:03pm on Thursday, August 2nd, 2012
I have a directory,Its permission is 700,I want permission to enter with root changed to 777.but,Prompt me "Permission denied". This is why. drwx------ 2 root root 0 Jul 30 14:05 gconfd-root [root@linux3 mnt]# chmod 777 gconfd-root chmod: changing permissions of `gconfd-root': Permission denied
vijayendra	Posted at 7:59am on Tuesday, August 7th, 2012
nice.. thkq..
Suman	Posted at 3:22am on Monday, August 13th, 2012
Hey Thanks! Was of very Good Help!
cvm	Posted at 12:09pm on Wednesday, August 15th, 2012
Very good explanation for chmod command. Thank you very much
Miguel	Posted at 11:58am on Monday, August 20th, 2012
hello blogger, i was redanig your posts on Correct Permission Problem In Suphp \| Web Hosting Tutorials and i actually liked them. one issue that i noticed whilst browsing through your blog that some of the links aren't working and giving error. this makes the redanig experience a little bit bad. you have a good blog and i would request you to revise the links so that fascinated folks can get all the info they want to have. Btw are you on twitter?? i would really like to follow you and also get updates in your blog.
Fallen3000	Posted at 7:24pm on Monday, August 20th, 2012
ok how do you enter non directories? and what does @ or + mean at the end?
Fallen3000	Posted at 9:14pm on Monday, August 20th, 2012
ok how do you enter non directories? and what does @ or + mean at the end?
zqbzwyfuelf	Posted at 2:00am on Tuesday, August 21st, 2012
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meredith1	Posted at 4:39pm on Wednesday, August 22nd, 2012
pretty good! thx
badbrlmkjw	Posted at 2:20pm on Thursday, August 23rd, 2012
Pla434 gcbazxgubges
sunset	Posted at 7:51am on Friday, August 24th, 2012
Very good post but there is an aspect to the permissions that I recently discovered and probably should be added to your otherwise excellent description. If you own a file but remove read permission for yourself, you will not be able to read the file regardless of the group and other permissions. Likewise, if you don't own a file but you belong to a group which is the group for the file, then if the group doesn't have read permission, you won't be able to read the file. Obviously the same applies to write and execute permissions.
Giri	Posted at 3:40am on Saturday, August 25th, 2012
Thnx useful one
Giri	Posted at 3:40am on Saturday, August 25th, 2012
Thnx useful one
Pavan Naidu	Posted at 10:26pm on Tuesday, August 28th, 2012
hai.. simply.. good frnds..this is useful for beginners..
Naeem Khan	Posted at 10:33pm on Thursday, September 13th, 2012
Really helpful
Kirti gupta	Posted at 9:43pm on Saturday, September 15th, 2012
nice decription
Anonymous	Posted at 7:56pm on Monday, September 17th, 2012
-rw-r--r--@ filename What is the @ for in the permission
Anonymous	Posted at 2:20pm on Monday, October 8th, 2012
What, you don't want to give a primer on binary to decimal conversion?! Yeesh, what a junk idea this chmod thing is. No wonder nobody uses Unix and Linux.
test	Posted at 9:13pm on Friday, October 26th, 2012
test
test	Posted at 9:13pm on Friday, October 26th, 2012
test
Neha Relwani	Posted at 11:35am on Sunday, October 28th, 2012
What if I put the permissions as 000..wat happens??
Anonymous	Posted at 7:33am on Thursday, November 8th, 2012
Good explanation with instances.
Anonymous	Posted at 7:34am on Thursday, November 8th, 2012
Good explanation with instances.
Anonymous	Posted at 4:45am on Friday, November 9th, 2012
good details
Bala	Posted at 4:47am on Friday, November 9th, 2012
Good and needfull information.
d	Posted at 5:07am on Thursday, November 15th, 2012
thank you very much, very helpful. i can now sleep at night
connor	Posted at 12:27pm on Wednesday, November 28th, 2012
Im trying to use a program to find out what the permission of the user is and if it doesn't include "x" change it to include "x". Any ideas on how to approach the problem would be greatly appreciated.
Impressive	Posted at 1:52am on Friday, November 30th, 2012
wow gold cheap gold for wow cheap safe wow gold
Izzy	Posted at 10:06pm on Sunday, December 16th, 2012
This was a big help. I totally got it, thanks I will be looking out for more of your work. Izzy, out
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Anonymous	Posted at 5:40am on Friday, January 11th, 2013
Heel verstandig dit te hebben gelezen. Thanks W
Anonymous	Posted at 4:27am on Tuesday, January 15th, 2013
Gives good understanding on chmod
syed	Posted at 6:01am on Friday, January 18th, 2013
good one
syed	Posted at 6:01am on Friday, January 18th, 2013
good one
Jonathan	Posted at 1:38pm on Thursday, January 31st, 2013
Thank You!
billCAP	Posted at 11:24am on Tuesday, February 19th, 2013
how can I list what directories a group has access to?
QP	Posted at 1:34pm on Thursday, March 7th, 2013
Very helpful.
Anonymous	Posted at 11:02am on Sunday, March 10th, 2013
good work
sandeep	Posted at 11:37pm on Wednesday, March 13th, 2013
superbb,,
Ram	Posted at 11:13pm on Tuesday, April 2nd, 2013
THank man .. May be little bit clear

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