Days of the Condor

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Clean bash profiles

Dec 10, 2012

Lately I’ve been more interested in writing Bash. However, as cool as Bash is for being able to pipe data all over the place, it has a really hard to read syntax. This makes understanding people’s 1000 line long Bash file tedious.

The more utility functions, aliases, and slight tweaks I add to my profile, the longer I have to spend each time I come back to it. I recently split out each of the sections into their own files to fix this.

My new profile is much shorter and is very clear.

# export common color escape sequences
source ~/Dropbox/dotfiles/colors

# source utility functions
for function in `find ~/Dropbox/dotfiles/bin/sh -type f`
  source $function

# aliases
source ~/Dropbox/dotfiles/aliases

# z script
source ~/z/

# system PATH
source ~/Dropbox/dotfiles/paths

export EDITOR=subl

eval "$(rbenv init -)"

symbol_formatting="$reset\n$computer_symbol "

PS1="\n\[\`if [[ \$? = "0" ]]; then echo '\e[32m\h\e[0m'; else echo '\e[31m\h\e[0m' ; fi\`\]:\w$yellow"'`__git_ps1`'"$symbol_formatting"

I can never remember the color escape sequences, so the first thing I do is source a file that exports common colors for easy use.

export red="\033[31m"
export yellow="\033[33m"
export green="\033[32m"
export blue="\033[34m"
export purple="\033[35m"
export cyan="\033[36m"
export reset="\033[0m"

Next, I make sure that I have access to all the utility functions I’ve been writing by sourcing each of them from a scripts directory.

I noticed that my aliases were getting a bit out of hand and were taking up a large part of my profile, so I pulled them into a file too.

This next one is really useful. z script is a Bash utility that Paul Irish mentioned in a talk. It allows you to cd into a directory by fuzzy matching directories in your recent bash history. For example, if you always cd into ~/matt/some/really/long/project/called/rainbow-unicorns, you could type z uni and z script would work its magic and take you there.

The next part is a matter of personal taste. I prefer using vertical space to horizontal, so I split my PATH variable assignment into another file. The old one used to have a bunch of junk all in one line.

export PATH=/path1:/path2:/more/paths: # etc

Here are how my paths look now.


PATH=$(printf "%s" "${path_directories[@]}")

export PATH

More verbose? Yes, but I’ll take it for clarity.

The rest isn’t too exciting, I assign my EDITOR of choice, configure rbenv, and then work black magic to make my prompt look the way I like.

Overall, splitting my profile into multiple files has been a useful project in learning Bash tricks. The only thing I’m not pleased with is how hard it is to understand the PS1 code. I’d like to pull that logic into a function to clear up the intent of the code but I haven’t quite figured out how yet.