In a bash shell, I want to take the take a given string that matches a regex, and then take the part of the string.
For example, given https://github.com/PatrickConway/repo-name.git, I want to extract the repo-name substring.
How would I go about doing this? Should I do this all in a shell script, or is there another way to approach this?
You can use the =~ matching operator inside a [[ ... ]] condition:
#!/bin/bash
url=https://github.com/PatrickConway/repo-name.git
if [[ $url =~ ([^/]*)\.git ]] ; then
echo "${BASH_REMATCH[1]}"
fi
Each part enclosed in parentheses creates a capture group, the corresponding matching substring can be found in the same position in the BASH_REMATCH array.
[...] defines a character class[/] matches a character class consisting of a single character, a slash^ negates a character class, [^/] matches anything but a slash* means "zero or more times"\. matches a dot, as . without a backslash matches any characterSo, it reads: remember a substring of non-slashes, followed by a dot and "git".
Or maybe a simple parameter expansion:
#!/bin/bash
url=https://github.com/PatrickConway/repo-name.git
url_without_extension=${url%.git}
name=${url_without_extension##*/}
echo $name
% removes from the right, # removes from the left, doubling the symbol makes the matching greedy, i.e. wildcards try to match as much as possible.
Here's a bashy way of doing it:
var="https://github.com/PatrickConway/repo-name.git"
basevar=${var##*/}
echo ${basevar%.*}
...which gives repo-name
