Latex <--> Gitlab markdown converter

functions.sh

latex_to_gitlab(){
    if [ $# -ne 1 ]
    then
        printf "usage: latex_to_gitlab [FILE]\n"
        return 1
    fi
    perl -077pi.bak -e 's/(\s)\$\$(.+?)\$\$/\1```math\2```/sg' "${1}"
    perl -077pi.bak -e 's/(\s)\$(.+?)\$/\1\$`\2`\$/sg' "${1}"
    return 0
}

# inverse of the above
gitlab_to_latex(){
    if [ $# -ne 1 ]
    then
        printf "usage: gitlab_to_latex [FILE]\n"
        return 1
    fi
    perl -077pi.bak -e 's/(\s)```\math(.+?)```/\1\$\$\2\$\$/sg' "${1}"
    perl -077pi.bak -e 's/(\s)\$`(.+?)`\$/\1\$\2\$/sg' "${1}"
    return 0
}

LATEX_TO_GITLAB.md

Simple Perl scripts which use regex search and replace to in-place convert Latex markdown files (which use $[MATH]$ and $$[MATH]$$) to Gitlab markdown (which uses $`[MATH]`$ and ```math [MATH]``` and vice versa.

One caveat: the $$[MATH]$$ style should have the math environment delimiters on separate newlines, so this works:

$$
[MATH]
$$

but the below and similar variations don't:

$$[MATH]$$

Additionally, the very first character in the file should not be $.