Nerdcred++;

The art of customizing your bash prompt

Created by
Pam Ocampo / @pmocampo
Rachel Walker / @raychatter

Why?

Increase your productivity by maximizing your terminal’s screen real estate.

  • Show the current version of Ruby you're running
  • Git status of current directory
  • Color-code different pieces of information
  • It looks cool! ʕ•ᴥ•ʔ

    • The Command Line Prompt

    PS1 controls the prompt on your terminal’s command line.

    The prompt usually looks like this (on Mac):

    hostname:~ username$


    What's your current prompt?
    Open the terminal and type 

    echo $PS1

    What does it return?

    \h:\W \u\$

    Let's change our terminal from this

    To this:

    Or this:

    Let's get started!

    Hello, Bash

    Open the terminal and type:

    PS1="Hello, Bash"

    Hello, Bash

    PS1="Hello, Bash"

    Persisting changes

    • Open your ~/.bashrc in the terminal 
      vim ~/.bashrc
open ~/.bashrc
emacs ~/.bashrc
    • Add your PS1 
      export PS1=">> "
    • Save
    • Apply 
      source ~/.bashrc

    Escape Sequences

    Remember this? 

    \h:\W \u\$

    How does that translate to this?

    hostname:~ username$

    Escape sequences!

    Escape Sequence Cheat Sheet

    \d the date in "Weekday Month Date"
    \H the hostname
    \h the hostname up to the first `.'
    \r carriage return
    \n newline
    \t current time in 24hr HH:MM:SS format
    \T current time in 12-hour HH:MM:SS
    \@ time in 12-hour am/pm
    \w current working directory
    \W basename of current working directory
    \# the command number of this command
    \! the history number of this command
    \\ a backslash
    \e an ASCII escape character (033)
    \u username of the current user

    Link to this sheet: http://git.io/vP7GgQ

    Escape Sequences Example

    Change your Bash prompt to match ours:

    (05:40 PM)(username@host:~/home)

    \d the date in "Weekday Month Date"
    \H the hostname
    \h the hostname up to the first `.'
    \r carriage return
    \n newline
    \t current time in 24hr HH:MM:SS format
    \T current time in 12-hour HH:MM:SS
    \@ time in 12-hour am/pm
    \w current working directory
    \W basename of current working directory
    \# the command number of this command
    \! the history number of this command
    \\ a backslash
    \e an ASCII escape character (033)
    \u username of the current user

    Escape Sequences Solution

    export PS1=”(\@)(\u@\h):\W “

    Colors!


    This is boring:

    (5:40 PM) (pamo@host):~/home 
    PS1="(\@)(\u@\h):\W "

    This is more fun:

    (05:40 PM)(pamo@host):~/home 
    PS1="(\[\033[0;36m\]\@\[\033[0;37m\])(\[\033[0;35m\]\u@\h\[\033[0;37m]\[\033[0;37m\]):\[\033[0;31m\]\W "

    Break it Down

    \[\033[0;COLORCODE\]

    • Contain the non-printable characters
    • Escape character
    • Bold (1) vs Normal (0) characters

    Color Codes

    • 30m - Black
    • 31m - Red
    • 32m - Green
    • 33m - Yellow
    • 34m - Blue
    • 35m - Purple
    • 36m - Cyan
    • 37m - White
    • 0 - Normal
    • 1 - Bold


    Link to this sheet: http://git.io/vP7GgQ

    Play with Colors!

    \[\033[0;COLORCODE\]

    Turn this

    (5:40 PM) (pamo@host):~/home

    Into this

    (05:40 PM)pamo@host:~/home

    Colors Solution

    export PS1="\[\033[0;36m\](\@)\[\033[0;32m\]\u@\h:\[\033[0;33m\]\w"

    Introducing "no color"

    • What happens when you type a command?
      • The text is all yellow!
    • Solution: "no color" command
      • \[\033[0m\]
    • Try it out!

    Variables

  • This is hard to read:
    PS1=”(\[\033[0;36m\]\@\[\033[0m\])(\[\033[0;35m\]\u\[\033[0m\]@\[\033[0;32m\]\h\[\033[0m\]):\[\033[0;33m\]\W\[\033[0m\]“

  • This is much easier to read:
    PS1=”(${CYAN}\@${NO_COLOR})(${PURPLE}\u${NO_COLOR}@${GREEN}\h${NO_COLOR}):${YELLOW}\W${NO_COLOR}“

    • Variables

    (05:40 PM)(pamo@host):~/home

    YELLOW="\[\033[0;33m\]"
CYAN="\[\033[0;36m\]"
PURPLE="\[\033[0;95m\]"
GREEN="\[\033[0;32m\]"
NO_COLOR="\[\033[0m\]"
PS1="(${CYAN}\@${NO_COLOR})(${PURPLE}\u${NO_COLOR}@${GREEN}\h${NO_COLOR}):${YELLOW}\W${NO_COLOR} "

    Draw it Out!

  • What do you want you prompt to look like?
  • Draw it out and then reference the cheat sheets to make it a REALITY

    • Demo time!

    Show off your prompt!

    Wrapping things up...

    Check out our repo for additional resources http://pamo.github.io/nerdcred/

    • Detailed explanation of the bash prompt
    • Link to these slides
    • Sample bash prompts - e.g. git branch status
    • ...and if you're feeling lazy, bash prompt builders!

    Gracias!

    Tweet us your feedback

    Pamela Ocampo @pmocampo
    Rachel Walker @raychatter