A glimpse at Unix Commands

Working in a terminal shell on a command line sounds like heaven for some developer, but hell for some others. Even though I would consider myself more technical than creative, i.e. more programmer than designer, it did quite happen a lot in the past that opening a terminal window (whether it was on Mac OSX or any other Unix-based machine) caused an attack of sweating. Well, I am exaggerating. But still, when I watched “the gurus” using the command line, I was always astonished how they could all keep all the myriads of commands and options in their heads. It is just a matter of practice and experience I guess. But if you don’t have that much of an experience, like I do, the following “cheat sheet” might help to get familiar with it and keep one or the other useful command in your head for the future.

Files and Directories

Change directory

cd [directory]

Examples

• cd ~ takes you to your users home directory

Resources

• cd command reference

Create new directory

mkdir [dirname]

Examples

• mkdir homedir creates a new directory ‘homedir’

Resources

• mkdir command reference

Delete a directory

rmdir [option] [directory]

Examples

• rmdir homedir remove the directory ‘homedir’
• rm -r directory remove a directory, even if files existed in that directory

Resources

• rmdir command reference

Move file f to directory d

mv f1 [f2...] d

Examples

• mv myfile.txt newdirectory/ moves the file myfile.txt to the directory newdirectory

Resources

• mv command reference

Rename directory d1 as d2

mv d1 d2

Examples

• mv alpha beta renames directory ‘alpha’ to ‘beta’

Resources

• mv command reference

Delete a file

rm [-f] [-i] [-R] [-r] [filenames | directory]

Examples

• rm myfile.txt removes the file myfile.txt without prompting the user
• rm -rf /tmp/* removes all files (including write-protected ones) within /tmp recursively (including directories)

Resources

• rm command reference

List contents of directory

ls [options] [pathnames]

Examples

• ls -a shows you all files, even files that are hidden (these files begin with a dot.)
• ls -d */ only list the directories in the current directory
• ls -lsa shows additional information about files (permission, size, hidden files, blocks etc.)
• ls -1 lists the contents with one entry on each line (without any add. info)

Resources

• ls command reference

Create symbolic link

ln -s [destination] [source]

Examples

• ln -s ~/dev/myproject/htdocs . symlinks current directory to stated directory
• ln -s /export/space/common/archive /archive create a symlink from…to… (speak: “/archive is gonna link to /export/space/common/archive”)

Resources

• ln command reference

Environment Information

OS information

uname -a

Change password

passwd

Create command alias (csh/tcsh)

alias name1 name2

Create command alias (ksh/bash)

alias name1="name2"

Remove command alias na

unalias name1[na2...]

Login securely to remote node

ssh nd

End terminal session

exit

Set env var to value v (csh/tcsh)

setenv name v

set environment variable to value v (ksh/bash)

export name="v"

execute a file as a tcl script

source

Examples

• source ~/.profile executes .profile in user home directory

Search

Search for Text in Files

grep [options] PATTERN [FILE...]

Examples

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