3 ms·
FWIW in bash I have 2 functions: path_add() { export PATH=$PATH:$(string_join ':' $@) } path_prepend() { PATH=$(string_join ':' "$@"):$PATH
by t43562 2y ago
FWIW in bash I have 2 functions:
path_add() {
export PATH=$PATH:$(string_join ':' $@)
}
path_prepend() {
PATH=$(string_join ':' "$@"):$PATH
export PATH
}
These can join an arbitrary list of paths to PATH. e.g.
path_add /usr/bin /usr/local/bin ~/bin
They depend on another one:
string_join() {
local join=$1; shift
local result=$1; shift
for p in "$@"; do
result="${result}${join}${p}"
done
echo -n "$result"
set +x
}
I also have ones for adding and prepending to LD_LIBRARY_PATH
- nsb1 2y agoI cribbed these from someplace - slightly different approach: ################################################################### # Add directory to path pathadd() { newelement=${1%/} if [ -d "$1" ] && ! echo $PATH | grep -E -q "(^|:)$newelement($|:)" ; then if [ "$2" = "after" ] ; then PATH="$PATH:$newelement" else PATH="$newelement:$PATH" fi fi } ################################################################### # Remove directory from path pathrm() { PATH="$(echo $PATH | sed -e "s;\(^\|:\)${1%/}\(:\|\$\);\1\2;g" -e \ 's;^:\|:$;;g' -e 's;::;:;g')" }
- ceph_ 2y agoI'm surprised both the blog post and all the other comments don't mention how it should have logic to check if the item exists in the path before adding it. Otherwise you get duplicates added everytime you source your config. Your function does that so +1. Though I'd use [[ $PATH =~ "(^|:)$newelement($|:)" ]] over grep -q but it functions the same.
- rascul 2y agoAnother option is to set the full $PATH value explicitly instead of doing an add thing for each directory. This avoids duplicates and the extra logic, but maybe isn't as convenient.
- simonmic 2y agoDo any of these guard against an empty value on either side ? "export PATH=$DIR:$PATH - That particular pattern is way too common, and is very dangerous if you consider the case when [$DIR or] $PATH (or whatever your variable is, like $LD_LIBRARY_PATH) isn’t set. Then, the value will be :/path/to/dir, which usually means both /path/to/dir and the current directory, which is usually both unexpected behaviour and a security concern."
- jlokier 2y agoThe compact one-liners below are similar but avoid adding duplicate items to PATH, so are fine to call in various init scripts. In Bash: path_append() { local p; for p; do [[ :"$PATH": =~ :"$p": ]] || PATH+=:$p; done; } path_prepend() { local p; for p; do [[ :"$PATH": =~ :"$p": ]] || PATH=$p:$PATH; done; } In portable POSIX shell: path_append() { for p; do case :"$PATH": in *:"$p":*) ;; *) export PATH="$PATH:$p" ;; esac; done; } path_prepend() { for p; do case :"$PATH": in *:"$p":*) ;; *) export PATH="$p:$PATH" ;; esac; done; }