Shell

Tip

You can loop up information about commands by executing:

$ man <name>

For example, to lookup ls execute:

$ man ls

Information

• uname display operating system name
• date display the date
• uptime show how long the operating system has been running
• whoami show the current user id
• man display the manual page for a command

Directory Operations

• pwd display working directory
• mkdir make a directory
• cd change directory
• ls list directory contents

ls Options

• -a include directory entries whose name begins with a .
• -R recuresively list subdirectories encountered
• -r reverse the order of the sort
• -t sort by time modified
• -S sort files by size
• -l list in log format
• -1 output one entry per line
• -m list files accross the page separated by commas
• -Q enclose entry names in double quotes

Searching

• grep print lines matching a pattern
• find dir -name "pattern" search dir for files matching pattern
• find dir -iname "pattern" the above but ignore case
• whereis locate the binary, source, manual page files for a command
• locate find files by name

grep Options

• -i ignore case
• -r recursive
• -v select non-matching lines
• -o show only the matching part of matching lines

File Operations

• touch change file timestamps
• cat concatenate files and print to stdout
• more file perusal filter for viewing
• less like more but supports backward movement
• file determine file type
• cp copy files and directories
• mv move (rename) files
• rm remove files or directories
• head display the first lines of files
• tail display the last lines of files
• chmod change file access permissions

Process Management

• ps report a snapshot of current processes
• top display linux process table
• kill terminate a process using process id
• pgrep lookup process based on name
• pkill kill process based on name
• killall kill processes by name