Clean up bash script

Question

Can someone clean up this part of bin bash script for me? I feel like i can write this so much cleaner.

Basically, what i want to do is:

• If $pluginexcl2 is defined that 2 different grep -v will be used
• If $pluginexcl1 is defined than only 1 grep -v
• If both are undefined, not to use grep -v.

Help is appreciated.

# Snygga curl koden
curl_url=$(curl -s https://api.github.com/repos/${pluginrepo}/releases/latest)
 
# Filtrera grep :D
if [ -n "${pluginexcl1}" ] && [ -n "${pluginexcl2}" ]; then
    echo "$curl_url" | grep -wo "$plugingrep" | grep -v "$pluginexcl1" | grep -v "$pluginexcl2" | wget -qi - -O "${pluginfile}"
elif [ -n "${pluginexcl1}" ]; then
    echo "$curl_url" | grep -wo "$plugingrep" | grep -v "$pluginexcl1" | wget -qi - -O "${pluginfile}"
else
    echo "$curl_url" | grep -wo "$plugingrep" | wget -qi - -O "${pluginfile}"
fi

Answer 1

Consolidate the two conditional grep -v operations into a single operation using an -Extended regex, combined with parameter substitution of a non-sensical string if the variables are not populated.

One idea to replace the entire if/elif/else/fi block:

echo "$curl_url" | grep -wo "$plugingrep" | grep -Ev "${pluginexcl1:-XXXX}|${pluginexcl2:-XXXX}" | wget -qi - -O "${pluginfile}"

Replace the XXXX with a string you're sure doesn't show up in the contents of $curl_url.

NOTES:

• I'm assuming OP's current code works as expected.
• I'm (obviously) unable to test this since we're not given sample contents of the referenced variables.

Answer 2

latest_release=$(wget -q -O - https://api.github.com/repos/"$pluginrepo"/releases/latest)

plugin_exclude=(
        ${pluginexcl1:+-e "$pluginexcl1"}
        ${pluginexcl2:+-e "$pluginexcl2"}
)

printf '%s\n' "$latest_release" |
grep -w -o -e "$plugingrep" |
if [ "${#plugin_exclude[@]}" -gt 0 ]; then
        grep -v "${plugin_exclude[@]}"
fi |
wget -q -i - -O "$pluginfile"

This puts the exclusion patterns into the array plugin_exclude if defined and non-empty. Each pattern is prepended with -e to avoid accidentally interpreting them as options to the grep command if they start with dashes and also to allow the excluding grep -v invocation to use two separate patterns.

The if statement is then collapsed into a single pipeline where the penultimate stage is a short if statement that applies the exclusion patterns if they exist (if the plugin_exclude array has elements).

---

The same code, but for the POSIX sh shell:

latest_release=$(wget -q -O - https://api.github.com/repos/"$pluginrepo"/releases/latest)

set --  ${pluginexcl1:+-e "$pluginexcl1"} \
        ${pluginexcl2:+-e "$pluginexcl2"}

printf '%s\n' "$latest_release" |
grep -w -o -e "$plugingrep" |
if [ "$#" -gt 0 ]; then
        grep -v "$@"
fi |
wget -q -i - -O "$pluginfile"

Answer 3

This substitution "^\b$" will match no word edge, which means the grep -v will exclude no lines for the undefined parameter(s).

# Snygga curl koden
curl_url=$(curl -s https://api.github.com/repos/${pluginrepo}/releases/latest)
 
# Filtrera grep :D

echo "$curl_url" | grep -wo "$plugingrep" | \
   grep -v "${pluginexcl1:-^\b$}\|${pluginexcl2:-^\b$}" | wget -qi - -O "${pluginfile}"

Answer 4

Try this..

curl_url=$(curl -s https://api.github.com/repos/${pluginrepo}/releases/latest)
grep_command="grep -wo \"$plugingrep\""
[ -n "${pluginexcl1}" ] && grep_command+=" | grep -v \"$pluginexcl1\""
[ -n "${pluginexcl2}" ] && grep_command+=" | grep -v \"$pluginexcl2\""
echo "$curl_url" | eval "$grep_command" | wget -qi - -O "${pluginfile}"

I didn't test all script, but i don't see any secret or monster. haha

Hope this help!