To get detailed help of these command, including the options available and how to use them, use

man command_name

or

help command_name

• cd - change the current directory
• ls - list directory contents
• mkdir - make directories
• mv - move (rename) files/directories
• rm - remove files/directories
• cp - copy files/directories
• touch - change file timestamps.
• chmod - change file access permissions
• rsync - faster, flexible replacement for rcp (remote file copy)
• scp - secure copy (remote file copy program)

• cat - concatenate files and print on the standard output
• head - output the first part of files
• tail - output the last part of files
• wc - print the number of newlines, words, and bytes in files
• more - a filter for paging through text one screenful at a time
• less - a program similar to more, but more powerful (and user friendly)
• grep - print lines matching a pattern
• diff - find differences between two files
• gvim (vi) - The GUI version of vim - a text editor that is upwards compatible to Vi.
• sed - a stream editor used to perform basic text transformations
• awk - pattern scanning and processing language

• ps - report a snapshot of the current processes
• top - display Linux tasks
• bg - resume the suspended job in the background, as if it had been started with & (useful after you suspend a command with Ctrl-z)
• kill - terminate a process
• exit - cause the shell to exit

• man - format and display the manual pages
• help - display helpful information about builtin commands
• date - print or set the system date and time
• locate - find files by name
• find - search for files in a directory hierarchy
• who - show who is logged on
• pwd - print name of current/working directory
• du - estimate file space usage
• df - report filesystem disk space usage
• which - shows the full path of (shell) commands
• history - display the command history list with line numbers

• echo - display a line of text
• source - read and execute commands from a file
• alias - prints the list of aliases or define new aliases
• gimp - an image manipulation and paint program
• ssh - a program for logging into a remote machine and for executing commands on a remote machine
• mount/umount - mount and unmount filesystems
• passwd - update a user's authentication tokens (password)
• nohup - run a command immune to hangups, with output to a non-tty
• rdesktop - Remote Desktop Protocol client (connects to windows computers)
• export - export supplied names (variables) to the environment of subsequently executed commands
• crontab - maintain crontab files for individual users (used to execute commands at scheduled time)