Bash script that checks for parts of current folderpath - bash

Question

Clean and simple: how do I check with bash for certain parts of the folder I'm currently in?
#!/usr/bin/sh
CURRENTFOLDER=$(pwd)
echo "${CURRENTFOLDER}"
CHECKFOLDER="/home/*/domains/*/public_html"
if [ $CURRENTFOLDER ! $CHECKFOLDER ]
then
echo "Current folder is not /home/user/domains/domain.com/public_html"
exit
fi
User and domain are variable, I don't need to know them for this checkup, just the 3 pre-defined folders in the variable CHECKFOLDER

Answer 1

There's a problem with this approach.
For example in bash the following expression evaluates to true:
[[ /www/user/domains/local/public_html == /www/*/public_html ]]
It is more accurate to use a bash regex:
[[ /www/user/domains/local/public_html =~ ^/www/[^/]+/public_html$ ]]
So your code would become:
#!/bin/bash
current_folder=$PWD
check_folder='^/home/[^/]+/domains/[^/]+/public_html$'
if ! [[ $current_folder =~ $check_folder ]]
then
echo "Current folder is not /home/user/domains/domain.com/public_html"
exit
fi
BTW, the shebang needs to be a bash, not sh. And it's kind of dangerous to capitalize your variables.

Answer 2

Try this (almost) Shellcheck-clean code:
#! /usr/bin/sh
curr_phpath=''
for phpath in /home/*/domains/*/public_html/; do
if [ "$phpath" -ef . ]; then
curr_phpath=$phpath
break
fi
done
if [ -z "$curr_phpath" ]; then
echo "Current folder is not /home/user/domains/domain.com/public_html" >&2
exit 1
fi
Because of aliasing mechanisms (e.g. symbolic links, bind mounts) it is very difficult in general to determine if two paths reference the same file or directory by comparing them textually. See How to check if two paths are equal in Bash? for more information. This solution uses a more reliable mechanism to determine if the current directory is one of the valid ones.
Since the shebang line references sh instead of bash, the code avoids Bashisms. It's been tested with both bash and dash (probably the most common non-Bash sh).
See Correct Bash and shell script variable capitalization for an explanation of why the code does not use ALL_UPPERCASE variable names.
The [ "$phpath" -ef . ] test is true if the .../public_html path being checked is the same directory as the current directory. The -ef operator is not in POSIX so it is not guaranteed to be supported by an sh shell, and Shellcheck (correctly) warns about it. However, it is supported in both bash and dash, and sh is usually one of those (on Linux at least).

Answer 3

You can save a step just by changing to the directory instead of checking.
Check your glob matches only one file first.
Then, cd to check it's a dir.
#! /bin/bash
IFS="$(printf '\n\t')"
files=( $(compgen -G '/home/*/domains/*/public_html') )
if [[ "${#files[#]}" != 1 ]]
then
printf 'Multiple matches\n' >&2
exit 1
fi
if ! cd "${files[0]}"
then
printf 'Cannot chdir\n'
exit 1
fi