Unix Cheat sheet

Unix Cheat sheet

Change Working Directory:

cd                  go to your login (home) directory
cd ~username        go to username's login (home) directory
cd ..               go up one directory level from here
cd ../..            go up two directory levels from here
cd /path/to/dir     go to <dir>
cd path/to/dir      go to path relative to here (no leading slash).

Make a directory:

mkdir   dirname        make a directory identified by 'dirname'

List files:

ls          list contents of current directory
ls -a       include files with "." (dot files)
ls -l       list contents in long format
ls -rt      list contents, sort by time modified in reverse order

Determine a file type:

file filename           show the content type of 'filename'

Display file contents:

cat   filename          show contents of filename
less  filename          show contents of filename one page at a time
head  filename          show first 10 lines of filename
tail  filename          show last 10 lines of filename
head -50 filename       show first 50 lines of filename

Move (or rename) a file or directory:

mv srcfile destfile    rename srcfile to destfile
mv srcfile destdir     move a file into the destdir directory
mv srcdir destdir      rename srcdir to destdir; if destdir exists, then move to srcdir to destdir
mv -i srcdir destdir   same as above, but prompt before overwriting

Copy a file or directory:

cp srcfile destfile    make a copy of srcfile called and call it destfile
cp srcfile destdir     make a copy of srcfile, and place it in the destdir directory
cp -R srcdir destdir   copy srcdir (and contents) to destdir
cp -i src dest         same as above, but prompt before overwriting

Remove a file:

rm filename         remove (delete) filename
rmdir dir           remove an empty directory
rm -r dir           remove a directory and its contents
rm -i filename      remove filename, but prompt before deleting

Redirection:

cmd1 | cmd2             "pipe" output from cmd1 to input of cmd2
command > filename      direct output of command to filename, replacing contents of filename

Search files for text string:

grep string filename        show lines containing string in filename
grep string filelist        show lines containing string in any file in filelist
grep -v string filelist     show lines not containing string
grep -i string filelist     show lines containing string, ignore case
grin pattern directory      recursive through directory; show lines of all ascii files that match pattern

Limit search with grep:

ls | grep pattern       show output of ls that matches pattern

Search directories for file name:

find . | grep pattern       recurse through current directory; show file names that match pattern
find ~ -name "*.nii"        recurse through home directory; show file names that end with '.nii'

Compress files or directories:

See: data compression

Show running process:

pgrep processname               show processes called 'processname'
ps -ef | grep username          show all processes owned by username

cssh pgrep processname          show jobs called 'processname' on all workstations
cssh ps -ef | grep usrname      show jobs owned by username on all workstations

Terminate a process that you own (running with your username):

ctrl-C              kill foreground process
kill pid#           kill process identified by pid number (see 'ps' above)
pkill processname   kill process identified by 'processname' (see 'pgrep' above)

Show system resources:

nxload              show resources available on all workstations
top                 show process information on this system
top -u username     show process information of username on this system

User information:

finger username     show information about username
w                   show who is logged in to this system

Show Sun Grid Engine queue:

qstats | less                   display SGE queue information one page at a time

Change password:

See: change password