| Command |
Description |
| ls |
Lists all files and directories in the present working directory |
| ls-R |
Lists files in sub-directories as well |
| ls-a |
Lists hidden files as well |
| ls-al |
Lists files and directories with detailed information like permissions,size, owner, etc. |
| cd or cd ~ |
Navigate to HOME directory |
| cd .. |
Move one level up |
| cd |
To change to a particular directory |
| cd / |
Move to the root directory |
| cat > filename |
Creates a new file |
| cat filename |
Displays the file content |
| cat file1 file2 > file3 |
Joins two files (file1, file2) and stores the output in a new file (file3) |
| mv file "new file path" |
Moves the files to the new location |
| mv filename new_file_name |
Renames the file to a new filename |
| sudo |
Allows regular users to run programs with the security privileges of the superuser or root |
| rm filename |
Deletes a file |
| man |
Gives help information on a command |
| history |
Gives a list of all past commands typed in the current terminal session |
| clear |
Clears the terminal |
| mkdir directoryname |
Creates a new directory in the present working directory or a at the specified path |
| rmdir |
Deletes a directory |
| mv |
Renames a directory |
| pr -x |
Divides the file into x columns |
| pr -h |
Assigns a header to the file |
| pr -n |
Denotes the file with Line Numbers |
| lp -nc , lpr c |
Prints "c" copies of the File |
| lp-d lp-P |
Specifies name of the printer |
| apt-get |
Command used to install and update packages |
| mail -s 'subject' -c 'cc-address' -b 'bcc-address' 'to-address' |
Command to send email |
| mail -s "Subject" to-address < Filename |
Command to send email with attachment |
| ls-l |
to show file type and access permission |
| Chown user |
For changing the ownership of a file/directory |
| Chown user:group filename |
change the user as well as group for a file or directory |
| echo $VARIABLE |
To display value of a variable |
| env |
Displays all environment variables |
| VARIABLE_NAME= variable_value |
Create a new variable |
| Unset |
Remove a variable |
| export Variable=value |
To set value of an environment variable |
| sudo adduser username |
To display value of a variable |
| sudo passwd -l 'username' |
Displays all environment variables |
| sudo userdel -r 'username' |
Create a new variable |
| sudo usermod -a -G GROUPNAME USERNAME |
Remove a variable |
| sudo deluser USER GROUPNAME |
To set value of an environment variable |
| finger |
Gives information on all logged in user |
| finger username |
Gives information of a particular user |
| SSH username@ip-address or hostname |
login into a remote Linux machine using SSH |
| Ping hostname="" or ="" |
To ping and Analyzing network and host connections |
| dir |
Display files in the current directory of a remote computer |
| cd "dirname" |
change directory to "dirname" on a remote computer |
| put file |
upload 'file' from local to remote computer |
| get file |
Download 'file' from remote to local computer |
| quit |
Logout |
| bg |
To send a process to the background |
| fg |
To run a stopped process in the foreground |
| top |
Details on all Active Processes |
| ps |
Give the status of processes running for a user |
| ps PID |
Gives the status of a particular process |
| pidof |
Gives the Process ID (PID) of a process |
| kill PID |
Kills a process |
| nice |
Starts a process with a given priority |
| renice |
Changes priority of an already running process |
| df |
Gives free hard disk space on your system |
| free |
Gives free RAM on your system |
