Unix Cheat Sheet


Help on any Unix command.
man {command}Type man rm to read the manual for the rm command.
whatis {command}Give short description of command.

List a directory
ls {path}It's ok to combine attributes, eg ls -laF gets a long listing of all files with types.
ls {path_1} {path_2}List both {path_1} and {path_2}.
ls -l {path}Long listing, with date, size and permisions.
ls -a {path}Show all files, including important .dot files that don't otherwise show.
ls -F {path}Show type of each file. "/" = directory, "*" = executable.
ls -R {path}Recursive listing, with all subdirs.
ls {path} | moreShow listing one screen at a time.

Change to directory
cd {dirname}There must be a space between.
cd ~Go back to home directory, useful if you're lost.
cd ..Go back one directory.

Make a new directory
mkdir {dirname}

Remove a directory
rmdir {dirname}Only works if {dirname} is empty.
rm -r {dirname}Remove all files and subdirs. Careful!

Print working directory
pwdShow where you are as full path. Useful if you're lost or exploring.

Copy a file or directory
cp {file1} {file2}
cp -r {dir1} {dir2}Recursive, copy directory and all subdirs.
cat {newfile} >> {oldfile}Append newfile to end of oldfile.

Move (or rename) a file
mv {oldfile} {newfile}Moving a file and renaming it are the same thing.
mv {oldname} {newname}

Delete a file
rm {filespec}? and * wildcards work like DOS should. "?" is any character; "*" is any string of characters.
ls {filespec}
rm {filespec}
Good strategy: first list a group to make sure it's what's you think...
...then delete it all at once.

View a text file
more {filename}View file one screen at a time.
less {filename}Like more, with extra features.
cat {filename}View file, but it scrolls.
cat {filename} | moreView file one screen at a time.

Edit a text file.
gedit {filename}Basic text editor

Create a text file.
cat > {filename}Enter your text (multiple lines with enter are ok) and press control-d to save.
gedit {filename}Create some text and save it.

Compare two files
diff {file1} {file2}Show the differences.
sdiff {file1} {file2}Show files side by side.

Other text commands
grep '{pattern}' {file}Find regular expression in file.
spell {file}Display misspelled words.
wc {file}Count words in file.
wc -l {file}Count the number of lines in a file.

Make an Alias
alias {name}='{command}'Put the command in 'single quotes'. More useful in your .bashrc file.

Wildcards and Shortcuts
*Match any string of characters, eg page* gets page1, page10, and page.txt.
?Match any single character, eg page? gets page1 and page2, but not page10.
[...]Match any characters in a range, eg page[1-3] gets page1, page2, and page3.
~Short for your home directory, eg cd ~ will take you home, and rm -r ~ will destroy it.
.The current directory.
..One directory up the tree, eg ls ...

Pipes and Redirection(You pipe a command to another command, and redirect it to a file.)
{command} > {file}Redirect output to a file, eg ls > list.txt writes directory to file.
{command} >> {file}Append output to an existing file, eg cat update >> archive adds update to end of archive.
{command} < {file}Get input from a file, eg sort < file.txt
{command} < {file1} > {file2}Get input from file1, and write to file2, eg sort < old.txt > new.txt sorts old.txt and saves as new.txt.
{command} | {command}Pipe one command to another, eg ls | more gets directory and sends it to more to show it one page at a time.
System info
dateShow date and time.
dfCheck system disk capacity.
duCheck your disk usage and show bytes in each directory.
du -hCheck your disk usage in a human readable format
printenvShow all environmental variables
uptimeFind out system load.
wWho's online and what are they doing?
topReal time processor and memory usage


Unix Directory Format

Long listings (ls -l) have this format:


    - file
    d directory,                                            * executable
    ^   symbolic links (?)  file size (bytes)   file name   / directory
    ^           ^               ^                  ^        ^
    drwxr-xr-x 11 valerie    16296  Mar  7 23:25 public_html/
    -rw-r--r--  1 valerie      256  Mar  8 23:42 index.html
                                            ^
     ^^^        user permission  (rwx)      date and time last modified
        ^^^     group permission (rwx)
           ^^^  world permission (rwx)


DOS and UNIX commands

ActionDOSUNIX
change directorycdcd
change file protectionattribchmod
compare filescompdiff
copy filecopycp
delete filedelrm
delete directoryrdrmdir
directory listdirls
edit a fileeditpico
environmentsetprintenv
find string in filefindgrep
helphelpman
make directorymdmkdir
move filemovemv
rename filerenmv
show date and timedate, timedate
show disk spacechkdskdf
show filetypecat
show file by screenstype filename | moremore
sort datasortsort