Customize Your Shell & Command Prompt

As mentioned in a previous post, we received some new MacBooks and a Mac Mini at work. Since most of my team prefers using PCs, I was able to get my hands on one. I immediately noticed how different it was from the one I use at home, so I started customizing it right away. I found I had forgotten how to do a couple things and it took me longer than I would have liked to search the web, so I’ve decided to dedicate a short post on how to customize your shell and command prompt in Mac OS X.

If you use Linux or Windows (think cygwin or git bash) this may apply to you too. If you don’t use any sort of shell, well, then you might just want this for future reference.

Apps

Terminal is the default app that comes with Mac OS X. Another great app is iTerm 2 (Free). It adds a lot of functionality that some users find lacking in Terminal.

General Preferences

Some programs that run the shell allow you to set the window size and buffer (essentially scrolling inside the limitations of the window). This is really helpful to setup before hand since lines that are too long will word wrap if you don’t have a large window buffer. This will inevitably happen at some point and it’s really annoying when it does, so take steps to prevent it now.

If you find you navigate to a specific directory every time you open the shell, it may be a good idea to tell the app to navigate to that directory when you open the shell. In Terminal, this can be found at Preferences >> Settings >> Shell; in iTerm 2 this can be found at Preferences >> Profiles >> General. There are a lot of other cool features (like window groupings) that you should checkout.

Appearance

The next thing you’re going to want to do is customize your shell’s color. I like the traditional black background with white or light gray text and some colorful highlighting like green or even just a plain grey.

For my shell’s font, I like to use Monaco 10pt.  Smaller text let’s me see more on the screen since I usually only let my shell take up one half of the screen. I enable bold fonts and bright colors for bold fonts, but I disable anti-aliasing (smooth edges) because I like that raw hacker feel ;).

.profile, .bash_profile or .bashrc

Some of the most important customization takes place in the .profile file. Every time your shell loads, it will run the commands found in the “profiles.” There are a number profiles some system-wide (e.g. /etc/profile), others personal (e.g. .profile). The bash man page provides useful information about the differences under the “INVOCATION” section:

When bash is invoked as an interactive login shell, or as a non-
interactive shell with the --login option, it first reads and executes
commands from the file /etc/profile, if that file exists. After
reading that file, it looks for ~/.bash_profile, ~/.bash_login, and
~/.profile, in that order, and reads and executes commands from the
first one that exists and is readable. The --noprofile option may be
used when the shell is started to inhibit this behavior.

When a login shell exits, bash reads and executes commands from the
file ~/.bash_logout, if it exists.

When an interactive shell that is not a login shell is started, bash
reads and executes commands from /etc/bash.bashrc and ~/.bashrc, if
these files exist. This may be inhibited by using the --norc option.
The --rcfile file option will force bash to read and execute commands
from file instead of /etc/bash.bashrc and ~/.bashrc.

Then at the bottom of the man page:

FILES
       /bin/bash
              The bash executable
       /etc/profile
              The systemwide initialization file, executed for login shells
       /etc/bash.bashrc
              The systemwide per-interactive-shell startup file
       /etc/bash.bash.logout
              The systemwide login shell cleanup file, executed when a login shell exits
       ~/.bash_profile
              The personal initialization file, executed for login shells
       ~/.bashrc
              The individual per-interactive-shell startup file
       ~/.bash_logout
              The individual login shell cleanup file, executed when a login shell exits
       ~/.inputrc
              Individual readline initialization file

In essence, .bash_profile is read upon login and .bashrc is read for each new shell opened since you can have multiple shell sessions running at once without logging in again. In Mac OS X, the .bash_profile overrides the .profile. I’ve run into some problems with .profile in the past, so I’ve actually switched everything to .bash_profile.

The next four sections will discuss:

  • How to change prompt escapes (bash)
  • How to change prompt color (bash)
  • How to create your personal “bin”
  • How to create aliases

Change Prompt Escapes

First, I like to customize the prompte e. I can’t stand it when the prompt is white and blends in with the rest of the text in the shell. The appearance of the prompt is stored in the environment variable $PS1. Try typing echo $PS1 in your shell. The text you see is a string coded with the display setting for your shell’s prompt. It might look something like this:

\h:\W \u$

In this example, the \h represents the host computer, \W the working directory and \u the current user. All this information makes sense if you were to use the CLI a lot. “Back in the old days,” people would interface between various servers or computers over a network (esp. in business scenarios). When you’d change to a different server, you’d want to know the host computer you were accessing. Not all the computers had GUIs. Thus \h would let you know which computer you were on; whether you were on yours or another.

The \u is common for similar reasons. Sometimes you use the su command to substitute user and you’ll want to know which user you are acting as.

The \W should be self explanatory. You don’t want to have to type pwd or ls all the time to know where you are at in the file hierarchy.

In my prompt, I’ve gotten rid of the host symbol (I don’t switch hosts often and when I do, the other prompt is usually different enough that I can tell I’m on a different machine) and replaced it with the history number prompt escape (\!). This escape let’s you know which number in the command history you have just typed. That way if you see a previous command that you’d like to repeat a couple lines up you just type !<number>. To view your complete command history, type the command history. A simplified version of my prompt looks like this:

\! \u:\W$

Here’s a comprehensive list of prompt escapes to add to your prompt:

\a         # an ASCII bell character (07)
\d         # the date in "Weekday Month Date" format (e.g., "Tue May 26")
\D{format} # the format is passed to strftime(3) and the result
           # is inserted into the prompt string an empty format
           # results in a locale-specific time representation.
           # The braces are required
\e         # an ASCII escape character (033)
\h         # the hostname up to the first '.'
\H         # the hostname
\j         # the number of jobs currently managed by the shell
\l         # the basename of the shell's terminal device name
\n         # newline
\r         # carriage return
\s         # the name of the shell, the basename of $0 (the portion following
           #   the final slash)
\t         # the current time in 24-hour HH:MM:SS format
\T         # the current time in 12-hour HH:MM:SS format
\@         # the current time in 12-hour am/pm format
\A         # the current time in 24-hour HH:MM format
\u         # the username of the current user
\v         # the version of bash (e.g., 2.00)
\V         # the release of bash, version + patch level (e.g., 2.00.0)
\w         # the current working directory, with $HOME abbreviated with a tilde
\W         # the basename of the current working directory, with $HOME
           # abbreviated with a tilde
\!         # the history number of this command
\#         # the command number of this command
\$         # if the effective UID is 0, a #, otherwise a $
\nnn       # the character corresponding to the octal number nnn
\\         # a backslash
\[         # begin a sequence of non-printing characters, which could be used
           #   to embed a terminal control sequence into the prompt
\]         # end a sequence of non-printing characters

Change Prompt Color

To color code your prompt on a Mac, use the following template:

\[\033[COLOR_CODE_HERE\]PROMPT_ESCAPE_OR_TEXT_HERE\[\033[0m\]

Most Linux distributions use a little different format:

\e[COLOR_CODE PROMPT_ESCAPE\e[0m

The first portion before the desired prompt escape or text only begins painting the chosen color (e.g., \[\033[1;34m\]). To stop painting a color, you have to reset to another color or turn color off (e.g., \[\033[0m\]).

Here’s a comprehensive list of color encoding:

# Regular Colors
\[\033[0;30m\] # Black
\[\033[0;31m\] # Red
\[\033[0;32m\] # Green
\[\033[0;33m\] # Yellow
\[\033[0;34m\] # Blue
\[\033[0;35m\] # Purple
\[\033[0;36m\] # Cyan
\[\033[0;37m\] # White

# High Intensty
\[\033[0;90m\] # Black
\[\033[0;91m\] # Red
\[\033[0;92m\] # Green
\[\033[0;93m\] # Yellow
\[\033[0;94m\] # Blue
\[\033[0;95m\] # Purple
\[\033[0;96m\] # Cyan
\[\033[0;97m\] # White

# Background
\[\033[40m\] # Black
\[\033[41m\] # Red
\[\033[42m\] # Green
\[\033[43m\] # Yellow
\[\033[44m\] # Blue
\[\033[45m\] # Purple
\[\033[46m\] # Cyan
\[\033[47m\] # White

# High Intensty backgrounds
\[\033[0;100m\] # Black
\[\033[0;101m\] # Red
\[\033[0;102m\] # Green
\[\033[0;103m\] # Yellow
\[\033[0;104m\] # Blue
\[\033[10;95m\] # Purple
\[\033[0;106m\] # Cyan
\[\033[0;107m\] # White

#Replace any leading leading 0; with 1; for bold colors
#Replace any leading 0; with 4; to underline

Once you’ve decided on the appropriate prompt add export PS1=”<custom prompt>” to your .profile. For example, this is what the line in my .profile looks like:

export PS1="\[\033[1;34m\]\!\[\033[0m\] \[\033[1;35m\]\u\[\033[0m\]:\[\033[1;35m\]\W\[\033[0m\]$ "

Add Personal “bin” to the PATH Variable

Every now and again you may want to create your own custom commands, scripts or programs for the CLI. Instead of mixing these in with the rest of the OS’s, just create your own personal “bin” folder and add it to your PATH variable so that you can run those commands from any folder in the shell.

export PATH=$PATH:/Users/Taylor/bin

Create & Use Aliases

Aliases are really nifty. They can save you a lot of extra effort for frequently used and/or lengthy commands. For example, I found that I liked to use ls -lhaG a lot more than just ls as follows:

alias ls='ls -lhaG'

Alias long commands that you’d forget or never want to type. I use Git to version my code. The git log command is very powerful and can include a lot of options. Instead of typing the various options every time, I use an alias called glg:

alias glg='git log --date-order --all --graph --format="%C(green)%h%Creset %C(yellow)%an%Creset %C(blue bold)%ar%Creset %C(red bold)%d%Creset%s"'

Conclusion

At the end of the day, this is what my .bash_profile looks like:

UPDATED 2014-04-02

##################
### MY ALIASES ###
##################

# git command autocompletion script
source ~/bin/git-completion.bash

# git commamands simplified
alias gst='git status'
alias gco='git checkout'
alias gci='git commit'
alias grb='git rebase'
alias gbr='git branch'
alias gad='git add -A'
alias gpl='git pull'
alias gpu='git push'
alias glg='git log --date-order --all --graph --format="%C(green)%h%Creset %C(yellow)%an%Creset %C(blue bold)%ar%Creset %C(red bold)%d%Creset%s"'
alias glg2='git log --date-order --all --graph --name-status --format="%C(green)%H%Creset %C(yellow)%an%Creset %C(blue bold)%ar%Creset %C(red bold)%d%Creset%s"'

# ls alias for color-mode
alias lh='ls -lhaG'

# lock computer
alias lock='/System/Library/CoreServices/"Menu Extras"/User.menu/Contents/Resources/CGSession -suspend'

# hibernation and sleep settings
alias hibernate='sudo pmset -a hibernatemode 25'
alias sleep='sudo pmset -a hibernatemode 0'
alias safesleep='sudo pmset -a hibernatemode 3'
alias smartsleep='sudo pmset -a hibernatemode 2'

# up 'n' folders
alias ..='cd ..'
alias ...='cd ../..'
alias ....='cd ../../..'
alias .....='cd ../../../..'

# simple ip
alias ip='ifconfig | grep "inet " | grep -v 127.0.0.1 | cut -d\ -f2'
# more details
alias ip1="ifconfig -a | perl -nle'/(\d+\.\d+\.\d+\.\d+)/ && print $1'"
# external ip
alias ip2="curl -s http://www.showmyip.com/simple/ | awk '{print $1}'"

# grep with color
alias grep='grep --color=auto'

# proxy tunnel
#alias proxy='ssh -D XXXX -p XXXX USER@DOMAIN'
# ssh home
#alias sshome='ssh -p XXXX USER@DOMAIN'

# processes
#alias ps='ps -ax'

# refresh shell
alias reload='source ~/.bash_profile'

###############################
### ENVIRONMENTAL VARIABLES ###
###############################

# Add homebrew sbin to PATH variable
export PATH=$PATH:/usr/local/sbin

# Add personal bin to PATH variable
export PATH=$PATH:/Users/Taylor/bin    # May be redundant; check ~/.bash_profile, /etc/profile, /etc/paths, /etc/bashrc

# Show dirty state in prompt when in Git repos
export GIT_PS1_SHOWDIRTYSTATE=1

# Change prompt
PS1_OLD=${PS1}
export PS1='\[\033[1;34m\]\!\[\033[0m\] \[\033[1;35m\]\u\[\033[0m\]:\[\033[1;35m\]\W\[\033[0m\] \[\033[1;92m\]$(__git_ps1 "(%s)")\[\033[0m\]$ '

What have you done to customize your shell or change your command prompt?

20 Comments

  1. alias ..=’cd ..’
    alias …=’cd ../..’
    alias ….=’cd ../../..’
    alias …..=’cd ../../../..’

    alias sup=’svn update’
    alias sco=’svn checkout’
    alias sci=’svn commit’

    alias ls=’ls -Gl’
    alias lsh=’ls -Gal’

    alias finder=’open .’
    alias back=’cd -‘
    alias clr=’clear’

    # quicklook –> ql photo.jpg
    alias ql=’qlmanage -p 2>/dev/null’

    # simple ip
    alias ip=’ifconfig | grep “inet ” | grep -v 127.0.0.1 | cut -d\ -f2′
    # more details
    alias ip1=”ifconfig -a | perl -nle’/(\d+\.\d+\.\d+\.\d+)/ && print $1′”
    # external ip
    alias ip2=”curl -s http://www.showmyip.com/simple/ | awk ‘{print $1}'”

    alias ping=”ping -c 5″

    alias grep=’grep –color=auto’

    alias game=’emacs -batch -l dunnet’
    # sleep computer
    alias iSleep=”osascript -e ‘tell application “Finder” to sleep'”
    alias history=’history’

    # folder shortcuts
    alias logs =’cd /User/Jared/JBoss/jboss-4.2.2/server/logs’
    # …

    # proxy tunnel
    alias proxy=’ssh -D XXXX -p XXXX USER@DOMAIN’
    # ssh home
    alias sshome=’ssh -p XXXX USER@DOMAIN’

    # processes
    alias ps=’ps -ax’

    # refresh shell
    alias reload=’source ~/.bash_profile’

    Reply

    1. A very nice addition indeed! Thanks for posting.

      Reply

  2. Awesome post Taylor! iTerm 2 is the bomb.

    Reply

  3. […] Then add the following code snippet to your .profile or .bash_profile file (See my post about customizing your shell for more details or to learn […]

    Reply

  4. […] the programs familiar to *Nix users in addition to the autocomplete functionality with Git. I can customize my shell and thank goodness for that! It definitely makes me more efficient and feel more at home. If […]

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  5. […] Customize Your Shell & Command Prompt | Taylor McGann’s Blog. […]

    Reply

  6. This is excellent. I really like the up ‘n’ and git aliases. Came looking for prompt customization and found much more goodness. Thanks.

    Reply

  7. […] Taylor McGann’s Blog – Customize Your Shell & Command Prompt […]

    Reply

  8. \D format documentation is listed here:

    https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/strftime.3.html

    And this is my custom prompt:

    export PS1=”\D{%Y%m%d-%T}-\[33[0;36m\]\u\[33[0;31m\]@\h \[33[0;33m\][ \W/ ] \[33[0;37m\]$\[33[0m\] “

    Reply

  9. Any thoughts on what to put in .profile versus .bashrc and .bash_profile?

    Reply

    1. I’ve updated the post to discuss the differences between the files. That said, I haven’t come across a scenario requiring me to put some code in one and not in another. Maybe if you wanted something to reload for each interactive prompt you would put it in the .bashrc? Can’t think of a good example because I’ve never had to.

      Reply

  10. Very helpful post, thanks!

    Reply

  11. […] I had to read this article like 10 times to wrap my head around what was actually happening and I’m hoping to cut that […]

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  12. […] Customize Your Shell & Command Prompt […]

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  13. […] My Mac OSX Bash Profile Customize Your Shell & Command Prompt […]

    Reply

  14. Just what I was looking for. Thanks.

    Reply

  15. […] .bash  //  iterm2 setup  //  Customize your shell and command prompt  //  Tuts+ tutorial for command line //  bash profile generator  //  Command line […]

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