Compression
Command Action
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 Gzip compression
tar xzf file.tar.gz extract a tar using Gzip
tar cjf file.tar.bz2 create a tar with Bzip2 compression
tar xjf file.tar.bz2 extract a tar using Bzip2
gzip file compresses file and renames it to file.gz
gzip -d file.gz decompresses file.gz back to file
Disk Quotas
Command Action
du -s -h ~ returns the disk size of your home directory (and all files/folder within it)
File Commands
Command Action
ls directory listing
ls -al formatted listing with hidden files
cd change to home directory
cd dir change directory to dir
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; – use with extreme caution –
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 10 lines of file
tail file output the last 10 lines of file
tail -f file output the contents of file as it grows, starting with the last 10 lines
File Permissions
Command
chmod octal file
Change the permissions of file to octal, which can be found spearately for user, group, and world by adding:
4 - read ®
2 - write (w)
1 - execute (x)
Examples:
chmod 777 - read, write, execute for all
chmod 755 - rwx for owner, rx for group and world
For more options, use command man chmod. For information on man see Linux Man (Manual) Pages.
Installation
Command Action
./configure
make
make install Install from source
dpkg -i pkg.deb install a package (Debian)
rpm -Uvh pkg.rpm install a package (RPM)
Network
Command Action
ping host ping host and output results
whois domain get whois information for domain
dig domain get DNS information for domain
dig -x host reverse lookup host
wget file download file
wget -c file continue a stopped download
Printing
Command Action
lpr filename Print the specified file filename
program | lpr -P printer Print output of the program program
lpr -#num-copies filename Print multiple copies of file filename
lpr -o sides-two-sided-long-edge filename Print file filename on both sides of paper
lpr -o page-ranges=range filename Print page ranges range (ex: 1-4,7,9-12) from file filename
lpr -o fit-to-page filename Print file filename so it scales to the page
lpr -o outputorder=reverse filename Print file filename in reverse order
Searching
Command Action
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
Shortcuts
A (k) next to the command donates a keyboard command, not a typed command.
Command Action
(k) Ctrl+C halts the current command
(k) Ctrl+Z stops the current command, resume with fg in the foreground or bg in the background
(k) Ctrl+D log out of current session, similar to exit
(k) Ctrl+W erases one word in the current line
(k) Ctrl+U erases the whole line
(k) Ctrl+R
!! repeats the last command
exit log out of current session
SSH
Command Action
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
System Info
Command Action
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 shows the manual for command; see more @ Linux Man (Manual) Pages
df show disk usage
du show directory space usage
free show memory and swap usage
wheris app show possible locations of app
which app show which app will be run by default
