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