cheat sheet for linux and unix

A small Linux cheat sheet, introducing the very basic and very essential commands for surviving at the Linux CLI.

Moving around in the file system
Command	Action
pwd	"Print working directory" - show what dir you're in.
ls	List the contents of a dir.
ls -l	List the contents of a dir and show additional info of the files.
ls -a	List all files, including hidden files.
cd	Change directory.
cd ..	Go to the parent directory.
Examining files
Command	Action
file	Determine the type of a file.
cat	Concatenate a file.
less	View text files and paginate them if needed.
Manipulating files and directories
Command	Action
cp	Copy a file.
cp -i	Copy a file and ask before overwriting.
cp -r	Copy a directory with its contents.
mv	Move or rename a file.
mv -i	Move or rename a file and ask before overwriting.
rm	Remove a file.
rm -r	Remove a directory with its contents.
rm -i	Ask before removing a file. Good to use with the -r option.
mkdir	Make a directory.
rmdir	Remove an empty directory.

rpm command cheat sheet for Linux

rpm is a powerful Package Manager for Red Hat, Suse and Fedora Linux. It can be used to build, install, query, verify, update, and remove/erase individual software packages. A Package consists of an archive of files, and package information, including name, version, and description:

Syntax	Description	Example(s)
rpm -ivh {rpm-file}	Install the package	rpm -ivh mozilla-mail-1.7.5-17.i586.rpm rpm -ivh --test mozilla-mail-1.7.5-17.i586.rpm
rpm -Uvh {rpm-file}	Upgrade package	rpm -Uvh mozilla-mail-1.7.6-12.i586.rpm rpm -Uvh --test mozilla-mail-1.7.6-12.i586.rpm
rpm -ev {package}	Erase/remove/ an installed package	rpm -ev mozilla-mail
rpm -ev --nodeps {package}	Erase/remove/ an installed package without checking for dependencies	rpm -ev --nodeps mozilla-mail
rpm -qa	Display list all installed packages	rpm -qa rpm -qa | less
rpm -qi {package}	Display installed information along with package version and short description	rpm -qi mozilla-mail
rpm -qf {/path/to/file}	Find out what package a file belongs to i.e. find what package owns the file	rpm -qf /etc/passwd rpm -qf /bin/bash
rpm -qc {pacakge-name}	Display list of configuration file(s) for a package	rpm -qc httpd
rpm -qcf {/path/to/file}	Display list of configuration files for a command	rpm -qcf /usr/X11R6/bin/xeyes
rpm -qa --last	Display list of all recently installed RPMs	rpm -qa --last rpm -qa --last | less
rpm -qpR {.rpm-file} rpm -qR {package}	Find out what dependencies a rpm file has	rpm -qpR mediawiki-1.4rc1-4.i586.rpm rpm -qR bash

{package} - Replace with actual package name

apt-get is the command-line tool for handling packages for Debian Linux which is use to:

Install/manage individual packages

Upgrade packages

Apply security patch(s)

Keep Debian system up to date

Download source .deb files

Front-end to many GUI and other utilities

Here is quick cheat sheet you will find handy while using apt-get at shell prompt:

Syntax	Description	Example(s)
apt-get install {package}	Install the new package. If package is installed then try to upgrade to latest version	apt-get install zip apt-get install lsof samba mysql-client
apt-get remove {package}	Remove/Delete an installed package except configuration files	apt-get remove zip
apt-get --purge remove {package}	Remove/Delete everything including configuration files	apt-get --purge remove mysql-server
apt-get update apt-get upgrade	Resynchronize the package index files and Upgrade the Debian Linux system including security update (Internet access required)	apt-get update apt-get upgrade
apt-get update apt-get dist-upgrade	Usually use to upgrade to Debian distribution. For example Woody to Sarge upgrade. 'dist-upgrade' in addition to performing the function of upgrade, also intelligently handles changing dependencies with new versions of packages; apt-get has a "smart" conflict resolution system, and it will attempt to upgrade the most important packages at the expense of less important ones if necessary.	apt-get update apt-get dist-upgrade

{package} - Replace with actual package name

dpkg is package manager for Debian Linux which is use to install/manage individual packages. Here is quick cheat sheet you will find handy while using dpkg at shell prompt:

Syntax	Description	Example
dpkg -i {.deb package}	Install the package	dpkg -i zip_2.31-3_i386.deb
dpkg -i {.deb package}	Upgrade package if it is installed else install a fresh copy of package	dpkg -i zip_2.31-3_i386.deb
dpkg -R {Directory-name}	Install all packages recursively from directory	dpkg -R /tmp/downloads
dpkg -r {package}	Remove/Delete an installed package except configuration files	dpkg -r zip
dpkg -P {package}	Remove/Delete everything including configuration files	dpkg -P apache-perl
dpkg -l	List all installed packages, along with package version and short description	dpkg -l dokg -l | less dpkg -l '*apache*' dpkg -l | grep -i 'sudo'
dpkg -l {package}	List individual installed packages, along with package version and short description	dpkg -l apache-perl
dpkg -L {package}	Find out files are provided by the installed package i.e. list where files were installed	dpkg -L apache-perl dpkg -L perl
dpkg -c {.Deb package}	List files provided (or owned) by the package i.e. List all files inside debian .deb package file, very useful to find where files would be installed	dpkg -c dc_1.06-19_i386.deb
dpkg -S {/path/to/file}	Find what package owns the file i.e. find out what package does file belong	dpkg -S /bin/netstat dpkg -S /sbin/ippool
dpkg -p {package}	Display details about package package group, version, maintainer, Architecture, display depends packages, description etc	dpkg -p lsof
dpkg -s {package} | grep Status	Find out if Debian package is installed or not (status)	dpkg -s lsof | grep Status

{package} - Replace with actual package name

Appendix C. DOS to Linux Cheat Sheet

Many Linux commands you type at a shell prompt are not that different from the commands you would type either in MS-DOS or in Windows (from the MS-DOS prompt). In fact, some commands are identical.

DOS and Linux Commands

What follows are some common commands used at the MS-DOS prompt in Windows 9x, and in Linux, as well as a basic example of how the command is used at the Linux shell prompt. Note that these commands usually have a number of options. To learn more about each command, read its associated man page (for example, type man ls at the shell prompt to read about the ls command).

Table C-1. Similar Commands

Command's Purpose	MS-DOS	Linux	Basic Linux Example
Copies files	copy	cp	cp thisfile.txt /home/thisdirectory
Moves files	move	mv	mv thisfile.txt /home/thisdirectory
Lists files	dir	ls	ls
Clears screen	cls	clear	clear
Closes prompt window	exit	exit	exit
Displays or sets date	date	date	date
Deletes files	del	rm	rm thisfile.txt
"Echoes" output on the screen	echo	echo	echo this message
Edits files with simple text editor	edit	pico[a]	pico thisfile.txt
Compares the contents of files	fc	diff	diff file1 file2
Finds a string of text in a file	find	grep	grep this word or phrase thisfile.txt
Formats a floppy	format a: (if floppy's in A:)	mke2fs (or mformat)	/sbin/mke2fs /dev/fd0 (/dev/fd0 is the Linux equivalent of A:)
Displays command help	command /?	man[c]	man command
Creates a directory	mkdir	mkdir	mkdir directory
Screens through a file	more	less[d]	less thisfile.txt
Renames a file	ren	mv	mv thisfile.txt thatfile.txt[e]
Shows your location in the file system	chdir	pwd	pwd
Changes directories with a specified path (absolute path)	cd pathname	cd pathname	cd /directory/directory
Changes directories with a relative path	cd ..	cd ..	cd ..
Displays the time	time	date	date
Shows amount of RAM and use	mem	free	procinfo
Notes: a. Pico is a simple text editor; other editors you can use in place of [b]pico include emacs and vi. b. This formats a disk for the DOS filesystem. c. Or you can use info for some commands. d. You can also another pager, called more, to scroll through a file a screen at at time. e. The mv command serves double-duty, because it can both move a file and, if you want to rename a file in the same directory, you "move" that file to the same directory with a new name, as in this example.

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