Linux shell/Bash prompt PS1, settings and history

This are steps to set up bash prompt showing git branch. This has been tested in Ubuntu 14 LTS

Edit vi ~/.bashrc

1. Uncomment #force_color_prompt=yes
   sed -i -E 's/^#(force_color_prompt=yes)/\1/g' ~/.bashrc
2. Find if [ "$color_prompt" = yes ]; then statement
3. then comment out #PS1= and add following code in bold

if [ "$color_prompt" = yes ]; then
        parse_git_branch() { git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/ (\1)/'; }
        PS1="\u@\h \[\033[32m\]\w\[\033[33m\]\$(parse_git_branch)\[\033[00m\] $ "
       #PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ ' #default colour prompt
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi

It will similar to

Reload shell without logging out

. ~/.bashrc
source ~/.bashrc
exec bash
exec "$BASH"

Differences

• source ~/.bashrc will preserve your current shell. Except for the modifications that reloading ~/.bashrc into the current shell (sourcing) makes, the current shell and its state are preserved, which includes environment variables, shell variables, shell options, shell functions, and command history.
• exec bash, or, more robustly, exec "$BASH"[1], will replace your current shell with a new instance, and therefore only preserve your current shell's environment variables (including ones you've defined ad-hoc). In other words: Any ad-hoc changes to the current shell in terms of shell variables, shell functions, shell options, command history are lost.

[1] exec bash could in theory execute a different bash executable than the one that started the current shell, if it happens to exist in a directory listed earlier in the $PATH. Since special variable $BASH always contains the full path of the executable that started the current shell, exec "$BASH" is guaranteed to use the same executable.

Bash coloured autocomplete of symlinks

Use bash --version | grep release to find out what version of Bash you are using.

To configure it add lines below to your ~/.inputrc or system-wide /etc/inputrc

Bash 4.3 readline adds a variable that enables color for tab completion to show different colors for executable files, directories, etc., during tab completion. Readline in the upcoming Bash 4.4 adds a variable which enables colour to indicate the matching portion of the string during tab completion.

set colored-stats on             #bash 4.3
set colored-completion-prefix on #bash >=4.4

You can see the values of these variables using

bind -v | grep color

Bash autocomplete the common string with ellipses

Add to your ~/.inputrc or system-wide /etc/inputrc file

set completion-prefix-display-length 2

When you TAB to autocomplete the common string if it's longer than 2 characters will be replaced with (...) ellipses

Bash key binding

• Readline This is what allows for all bash keybindings, colouring etc..

Resources

• CustomizingBashPrompt Ubuntu wiki
• Git Bash Prompt repo project Great informative Git prompt