| Command | Description | Usage |
| apt-get | Command-line tool for handling packages, and may be considered
the user’s “back-end” to other tools using the APT library. | $ apt-get install <package_name> |
| cat | Copies each FILE (‘-’ means standard input), or standard input if
none are given, to standard output. | $ cat content.txt |
| cd | Takes you to a directory | $ cd /home/local/ |
| chmod | Changes the access permissions of the named files. | $ chmod 755 content.txt |
| cp | copies files (or, optionally, directories). The copy is completely
independent of the original. You can either copy one file to another,
or copy arbitrarily many files to a destination directory. | $ cp file.txt /home/user/ |
| df | Reports the amount of disk space used and available on file
systems. | $ df |
| du | Reports the amount of disk space used by the set of specified files
and for each subdirectory (of directory arguments) | $ du |
| echo | Writes each given STRING to standard output, with a space between
each and a newline after the last one. | $ echo ‘HELLO’ |
| find | Searches the directory tree rooted at each file name FILE by
evaluating the EXPRESSION on each file it finds in the tree. | $ find -iname “HelloWorld.java” |
| grep | Prints lines that contain a match for a pattern | $ grep -r “arjun” * |
| hostname | Prints the name of the current host system. With one argument, it sets
the current host name to the specified string. You must have appropriate privileges to set the host
name. | $ hostname
$ hostname ‘Arjun’
$ hostname -I |
| locate | For each PATTERN given ‘locate’ searches one or more file name
databases returning each match of PATTERN. | $ locate *mp3* |
| ls | Lists information about files (of any type, including
directories). | $ ls |
| man | An interface to the on-line reference manuals | $ man |
| mkdir | Creates directories with the specified names | $ mkdir NewDirectory |
| mv | Moves or renames files (or directories). | $ mv file.txt /home/user/samples/ |
| nano | GNU ‘nano’ is a small and friendly text editor that comes by default
with linux. | $ nano content.txt |
| ping | Uses the ICMP protocol’s mandatory ECHO_REQUEST datagram to elicit an ICMP ECHO_RESPONSE from a host or gateway. | $ ping ‘www.google.com’ |
| pwd | Prints the name of the current directory | $ pwd |
| rm | Removes each given FILE. By default, it does not remove
directories. | $ rm textfile.txt |
| rmdir | Removes empty directories | $ rmdir NewDirectory |
| sed | sed is a stream editor. In a DOS file you could find \r\n in the end of each line. sed command converts the DOS file format to Unix file format. | $ sed ‘s/.$//’ <filename> |
| shutdown | Shutdown may be used to halt, power-off or reboot the machine. | $ shutdown -h now |
| sort | Sorts, merges, or compares all the lines from the given files, or
standard input if none are given or for a FILE of ‘-’. By default,
‘sort’ writes the results to standard output. | $ sort <sample.txt>
$ sort sample.txt |
| ssh | Program for logging into a remote machine and for executing commands on a remote machine. It is intended to provide secure encrypted communications between two untrusted hosts over an insecure network. | $ ssh -l arjun ‘www.google.com’ |
| sudo | Allows a permitted user to execute a command as the superuser or another user, as specified by the security policy. | $ sudo rm textfile.txt |
| tar | Tar stores and extracts files from a tape or disk archive. | $ tar -cvf images.tar /home/arjun/images/
$ tar -xvf images.tar |
| touch | Changes the access and/or modification times of the specified
files. | $ touch file.txt |
| uname | Prints information about the machine and operating system it is
run on. | $ uname |
| vi | It can be used to edit all kinds of plain text. It is especially useful for
editing programs. | $ vi HelloWorld.java |
