GNU/Linux File/Directory details


Example

The ls command has several options that can be used together to show more information.

Details/Rights

The l option shows the file permissions, size, and last modified date. So if the root directory contained a dir called test and a file someFile the command:

user@linux-computer:~$ ls -l

Would output something like

-rw-r--r-- 1 user users   70 Jul 22 13:36 someFile.txt
drwxrwxrwx 2 user users 4096 Jul 21 07:18 test

The permissions are in format of drwxrwxrwx. The first character represents the file type d if it's a directory - otherwise. The next three rwx are the permissions the user has over the file, the next three are the permissions the group has over the file, and the last three are the permissions everyone else has over the file.

The r of rwx stands for if a file can be read, the w represents if the file can be modified, and the x stands for if the file can be executed. If any permission isn't granted a - will be in place of r, w, or x.

So from above user can read and modify someFile.txt but the group has only read-only rights.

To change rights you can use the chmod ### fileName command if you have sudo rights. r is represented by a value of 4, w is represented by 2, and x is represented by a 1. So if only you want to be able to modify the contents to the test directory

Owner rwx = 4+2+1 = 7
Group r-x = 4+0+1 = 5
Other r-x = 4+0+1 = 5

So the whole command is

chmod 755 test

Now doing a ls -l would show something like

drwxr-xr-x 2 user users 4096 Jul 21 07:20 test

Readable Size

Used in conjunction with the l option the h option shows file sizes that are human readable. Running

user@linux-computer:~$ ls -lh

Would output:

total 4166
-rw-r--r-- 1 user users   70 Jul 22 13:36 someFile.txt
drwxrwxrwx 2 user users 4.0K Jul 21 07:18 test

Hidden

To view hidden files use the a option. For example

user@linux-computer:~$ ls -a

Might list

.profile
someFile.txt
test

Total Directory Size

To view the size of the current directory use the s option (the h option can also be used to make the size more readable).

user@linux-computer:~$ ls -s

Outputs

total 4166
someFile.txt      test

Recursive View

Lets say test directory had a file anotherFile and you wanted to see it from the root folder, you could use the R option which would list the recursive tree.

user@linux-computer:~$ ls -R

Outputs

.:
someFile.txt    test

./test:
anotherFile