Building a portable $PATH
I regularly swap between several different Linux instances, which all share a common shell configuration file. One of my pet nuisances is that the $PATH variable ends up swelling in size to accommodate for all of the setup-specific directories for binaries, leading to a bloated variable full of directories which may not even exist on the specific machine.
I had a few minutes to burn today so I wrote a small snippet for my .bashrc that allows me to maintain a list of all the desired PATH directories which are then added on an as-needed basis, only if the directory exists on the current system:
# The list of directories to add to the path. Directories
# are added sequentially from first to last. A directory
# is only added if it exists.
path_dirs=( \
~/bin \
~/.local/bin \
~/emacs/bin \
~/android-sdks/platform-tools \
/usr/lib/ccache \
/usr/local/bin \
/usr/contrib/bin \
/opt/bin \
/bin \
/usr/bin \
/usr/local/games \
/usr/games \
)
# Build path from directory list
unset PATH
for d in "${path_dirs[@]}"; do
test -d $d && PATH=$PATH:$d
done
# Strip the leading ':' from the path
export PATH=${PATH:1}
# Respect the environment
unset path_dirs
Lovely, now I have a neat and tidy PATH once again. Why didn’t I fix this before?