UNIX Command Cheat Sheet
Carnegie Observatories Summer Research Program
Every command and filename is CaSe sEnSiTiVe!
Command Description Examples and Options
<tab> Attempt to autocomplete Use this to speed up typing/avoid typos
Navigating Directories
ls List the contents of the directory. ls -larth /home/mcuser/science/code
cd Change directory. cd /home/mcuser/science
pwd present working directory. pwd
*Wild card, any number of chars. ls *.txt
?Wild card, 0 or 1 characters. ls foo?.txt
.Current directory. cd .
.. Directory one level up. cd ..
~Home directory. cd ~
-Previous directory. cd -
Modifying Directories and Files
mkdir Make new empty directory. mkdir MyNewDirectory
rmdir Remove empty directory. rmdir MyNewDirectory
mv Move files (overwrites destination). mv -i foo.txt foo2.txt
cp Copy files (overwrites destination). cp -i ../foo.txt .
rm Remove files. CANNOT UNDO! rm -i foo.txt
chmod
Change file permissions.
rwx = read, write, execute.
ugoa = user, group, other, all.
chmod a+rwx badger.txt
chmod o-wx badger.txt
chmod u+x myscript.sh
Viewing Files in Terminal
less View files in terminal window. less foo.txt
cat Concatenate files. cat foo1.txt foo2.txt
head Display first 10 lines. head -20 foo.txt
tail Display last 10 lines. tail -f logfile.txt
Searching
grep Search for word(s) in a file.
grep myvarname *.txt
grep rodent *.txt
grep "Hello World" *.txt
find Search a path for files/directories
that match some specification.
find playground -name "*.txt"
find playground -type d
find playground -not -name "*.txt"
Environment Variables
$HOME Home directory. workpath=$HOME/playground
$SHELL Shell name. echo $SHELL
$USER User name. echo $USER
$PATH Paths to look in for executables. PATH=${PATH}:/my/new/program/path/bin
env List environment vars and values. env | less
