Unix/Linux Command Reference

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File Commands
ls directory listing
ls -al formatted listing with hidden files
cd dir - change directory to dir
cd change to home
pwd show current directory
mkdir dir create a directory dir
rm file delete file
rm -r dir delete directory dir
rm -f file force remove file
rm -rf dir force remove directory dir *
cp file1 file2 copy file1 to file2
cp -r dir1 dir2 copy dir1 to dir2; create dir2 if it
doesn't exist
mv file1 file2 rename or move file1 to file2
if file2 is an existing directory, moves file1 into
directory file2
ln -s file link create symbolic link link to file
touch file create or update file
cat > file places standard input into file
more file output the contents of file
head file output the first 1 lines of file
tail file output the last 1 lines of file
tail -f file output the contents of file as it
grows, starting with the last 1 lines
Process Management
ps display your currently active processes
top display all running processes
kill pid kill process id pid
killall proc kill all processes named proc *
bg lists stopped or background !obs; resume a
stopped !ob in the background
fg brings the most recent !ob to foreground
fg n brings !ob n to the foreground
File Permissions
chmod octal file change the permissions of file
to octal, which can be found separately for user,
group, and world by adding"
# read $r%
& write $w%
1 execute $x%
'xamples"
chmod 777 read, write, execute for all
chmod 755 rwx for owner, rx for group and world
(or more options, see man chmod)
SSH
ssh user@host connect to host as user
ssh -p port user@host connect to host on port
port as user
ssh-copy-id user@host add your key to host for
user to enable a keyed or passwordless login
Searching
grep pattern files search for pattern in files
grep -r pattern dir search recursively for
pattern in dir
command | grep pattern search for pattern in the
output of command
locate file find all instances of file
System Info
date show the current date and time
cal show this month's calendar
uptime show current uptime
w display who is online
whoami who you are logged in as
finger user display information about user
uname -a show kernel information
cat /proc/cpuinfo cpu information
cat /proc/meminfo memory information
man command show the manual for command
df show disk usage
du show directory space usage
free show memory and swap usage
whereis app show possible locations of app
which app show which app will be run by default
Compression
tar cf file.tar files create a tar named
file.tar containing files
tar xf file.tar extract the files from file.tar
tar czf file.tar.gz files create a tar with
*+ip compression
tar xzf file.tar.gz extract a tar using *+ip
tar cf file.tar.bz2 create a tar with ,+ip&
compression
tar xf file.tar.bz2 extract a tar using ,+ip&
gzip file compresses file and renames it to
file.gz
gzip -d file.gz decompresses file.gz back to
file
Network
ping host ping host and output results
whois domain get whois information for domain
dig domain get -./ information for domain
dig -x host reverse lookup host
wget file download file
wget -c file continue a stopped download
Installation
0nstall from source"
!/configure
make
make install
dpkg -i pkg.deb install a package $-ebian%
rpm -"vh pkg.rpm install a package $123%
Shortcuts
#trl$# halts the current command
#trl$% stops the current command, resume with
fg in the foreground or bg in the background
#trl$& log out of current session, similar to exit
#trl$' erases one word in the current line
#trl$" erases the whole line
#trl$( type to bring up a recent command
)) - repeats the last command
exit log out of current session
* use with extreme caution)
Ubuntu Reference
Privileges
sudo command run command as root
sudo -s open a root shell
sudo -s -u user open a shell as user
sudo -k forget sudo passwords
gksudo command visual sudo dialog (GNOME)
kdesudo command visual sudo dialog (KDE)
sudo visudo edit /etc/sudoers
gksudo nautilus root file manager (GNOME)
kdesudo konqueror root file manager (KDE)
passwd change our password
Display
sudo /etc/init.d/gdm restart restart ! and
return to login (GNOME)
sudo /etc/init.d/kdm restart restart ! and
return to login (KDE)
(file) /etc/X11/xorg.conf displa
configuration
sudo dexconf reset "org#conf configuration
Ctrl+Alt+Bksp restart ! displa if fro$en
Ctrl+Alt+N switch to tt N
Ctrl+Alt+! switch %ac& to ! displa
System Services
start service start 'o% service ((pstart)
stop service stop 'o% service ((pstart)
status service chec& if service is running
((pstart)
/etc/init.d/service start start service
()s*)
/etc/init.d/service stop stop service ()s*)
/etc/init.d/service status chec& service
()s*)
/etc/init.d/service restart restart service
()s*)
runlevel get current runlevel
Package Management
apt-get update refresh availa%le updates
apt-get upgrade upgrade all pac&ages
apt-get dist-upgrade upgrade with pac&age
replacements+ upgrade (%untu version
apt-get install pkg install pkg
apt-get purge pkg uninstall pkg
apt-get autoremove remove o%solete pac&ages
apt-get -f install tr to fi" %ro&en pac&ages
dpkg --configure -a tr to fi" %ro&en
pac&ages
dpkg -i pkg.deb install file pkg.deb
(file) /etc/apt/sources.list ,-. repositor
list
Network
ifconfig show networ& information
iwconfig show wireless information
sudo iwlist scan scan for wireless networ&s
sudo /etc/init.d/networking restart reset
networ& for manual configurations
(file) /etc/network/interfaces manual
configuration
ifup interface %ring interface online
ifdown interface disa%le interface
Special Packages
u"untu-desktop standard (%untu environment
ku"untu-desktop KDE des&top
xu"untu-desktop !/0E des&top
u"untu-minimal core (%untu utilities
u"untu-standard standard (%untu utilities
u"untu-restricted-extras non1free2 %ut useful
ku"untu-restricted-extras KDE of the a%ove
xu"untu-restricted-extras !/0E of the a%ove
"uild-essential pac&ages used to compile
programs
linux-image-generic latest generic &ernel
image
linux-#eaders-generic latest %uild headers
Firewall
ufw ena"le turn on the firewall
ufw disa"le turn off the firewall
ufw default allow allow all connections %
default
ufw default den$ drop all connections %
default
ufw status current status and rules
ufw allow port allow traffic on port
ufw den$ port %loc& port
ufw den$ from ip %loc& ip adress
Application Names
nautilus file manager (GNOME)
dolp#in file manager (KDE)
konqueror we% %rowser (KDE)
kate te"t editor (KDE)
gedit te"t editor (GNOME)
System
Recovery 1 .pe the phrase 34E5)(67 while
holding down ,lt and )s48 (-rint)crn) with
a%out 9 second %etween each letter# :our sstem
will re%oot#
ls"%release -a get (%untu version
uname -r get &ernel version
uname -a get all &ernel information
1. Prefix commands with sudo to run.
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