Linux Filesystem Commands

df [options] [device name] : It displays the filesystem usage related information
-a : Displays all the filesystems
-i : Gives inode usage information
-h : Displays in human readable format. Shows quantified byte information

Example -:

$ df -a
Filesystem       1K-blocks    Used Available Use% Mounted on
/dev/sda1          7608792 2469924   4729320  35% /

proc                     0       0         0    - /proc
sysfs                    0       0         0    - /sys
none                     0       0         0    - /sys/fs/fuse/connections
none                     0       0         0    - /sys/kernel/debug
none                     0       0         0    - /sys/kernel/security
udev                244408       4    244404   1% /dev
devpts                   0       0         0    - /dev/pts
tmpfs               101288     772    100516   1% /run
none                  5120       0      5120   0% /run/lock
none                253216     124    253092   1% /run/shm
gvfs-fuse-daemon         0       0         0    - /home/mahesh/.gvfs
/dev/sr0             62658   62658         0 100% /media/VBOXADDITIONS_4.3.6_

91406
 

du [options] [pattern]  :  Displays space usage on files and directories
-c : Displays grand total for all the arguments
-h : Displays in human readable format. Shows quantified byte information
Example -:

$ du -ahc
0 ./centos/6
8.0K ./centos
4.0K ./samplefile.txt
0 ./ubuntu/ub10
4.0K ./ubuntu
16K .
16K total

ls [options] [filepattern] : Lists out directories and file entries from the given pattern
-a : Displays all the files including . &  ..
-r : Lists all the files in directories recursively
-l : Displays long list consisting of permissions on each file and other details
-d : Lists directories and not their content
-x : Displays sorted list by extension of the file
-s : Sorts output according to file size
-u : Displays sorted list by the access time
Example -:

$ ls -la
total 160
drwxr-xr-x 20 mahesh mahesh  4096 Mar 24 00:00 .
drwxr-xr-x  3 root   root    4096 Mar  9 01:23 ..
-rw-r--r--  1 mahesh mahesh   220 Mar  9 01:23 .bash_logout
-rw-r--r--  1 mahesh mahesh  3486 Mar  9 01:23 .bashrc
drwx------ 14 mahesh mahesh  4096 Mar 24 00:00 .cache
drwx------ 10 mahesh mahesh  4096 Mar 24 00:11 .config
drwx------  3 mahesh mahesh  4096 Mar  9 01:36 .dbus
drwxr-xr-x  2 mahesh mahesh  4096 Mar 24 00:11 Desktop
-rw-r--r--  1 mahesh mahesh    25 Mar 23 19:50 .dmrc
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Documents
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Downloads
-rw-r--r--  1 mahesh mahesh  8445 Mar  9 01:23 examples.desktop
drwx------  3 mahesh mahesh  4096 Mar 23 19:51 .gconf
drwx------  4 mahesh mahesh  4096 Mar  9 01:37 .gnome2
-rw-rw-r--  1 mahesh mahesh   142 Mar 23 19:51 .gtk-bookmarks
dr-x------  2 mahesh mahesh     0 Mar 23 19:51 .gvfs
-rw-------  1 mahesh mahesh   724 Mar 23 19:51 .ICEauthority
drwxr-xr-x  3 mahesh mahesh  4096 Mar  9 01:36 .local
drwx------  3 mahesh mahesh  4096 Mar  9 01:37 .mission-control
drwx------  4 mahesh mahesh  4096 Mar 24 00:00 .mozilla
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Music
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Pictures
-rw-r--r--  1 mahesh mahesh   675 Mar  9 01:23 .profile
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Public
drwx------  2 mahesh mahesh  4096 Mar 23 19:51 .pulse
-rw-------  1 mahesh mahesh   256 Mar  9 01:36 .pulse-cookie
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Templates
drwxr-xr-x  2 mahesh mahesh  4096 Mar  9 01:36 Videos
-rw-------  1 mahesh mahesh    62 Mar 23 19:50 .Xauthority
-rw-------  1 mahesh mahesh 23406 Mar 24 02:44 .xsession-errors
-rw-------  1 mahesh mahesh 12494 Mar 16 15:11 .xsession-errors.old 

mkdir [options] [directory-name] : Creates a new directory by the given directory-name
-m : Sets file mode
-p  : Creates parent directories if it does not exists.
Example -:

$ mkdir testdir

The above command will create a directory named "testdir"

 touch [options] [pattern] : Updates the timestamp of a file, If the file does not exists by default options creates it.
-a : Changes the access time only
-c : Do not create the file
-t  : Give a timestamp to use instead of current time
Example -:

$ touch testfile.txt

Creates "testfile.txt" if it does not exists, else it only updates timestamp of the "testfile.txt".

shred [options] [file_pattern] : Enables to overwrite a file to hide its content, also allows to delete file data in secured manner.
-s : This followed by number of bytes, will shred those many bytes
-n : Number of pattern iterations to run
-z : Add a final overwrite with zero to hide shredding
-u : Truncate and remove the file after overwriting
 Example -:

$ shred file1.txt file2.txt

The above command will destroy file1.txt and file2.txt completely, so not be able to recover even using any recovery utilities

rm [options] [file_pattern] : Remove the file
-f : Force removal
-i : Prompt before removal of each file 
-r : Deletes directories and their contents recursively.
Example -:

$ rm -rf testdir

Removes forcefully and recursively all the files in "testdir" as well as removes "testdir" directory.

mv [options] [from_pattern] [to_file] : Move or Rename a file
-f  : Do not prompt before overwriting
-i  : Interactive, prompts before moving
-n : Do not overwrite an existing file
Example -:

$ mv old_name new_name

Above command renames the "old_name" file/directory to "new_name".

$ mv alphonso basket/mango

Moves a file to another directory and rename it:

tar [options] [tar_file] [pattern] : Creates, Extracts an archive.
-c  : Creates a new tar archive
-f  : Specify an tar archive file to use
-t  : List the contents
-v : Verbose mode
-x : Extracts the archive contents
-z : Compress/Decompress through gzip
-j : Compress/Decompress through bzip2
Example -:

$ tar -cvf techdarting-04-14.tar /home/techdarting/
/home/techdarting/
/home/techdarting/bass.sh
/home/techdarting/openmpi-2.1.4.tar.gz
/home/techdarting/toolkit_pram.rpm

cd [directory] : Change directory

chown [options]  [mode] [file_name] : Enables to change the ownership of a directory, file etc.
-R : Recursively change ownership.

chmod [options] [user] [file_name] :  Enables to change the permission of a file, directory, etc.
-R : Recursively change permissions