Bugfix - add trailing slash to install script, enabling jq to be installed where it is not already present

[MysterAitch]

Notes
I noted recently that a fresh install to a rasperry pi / raspbian OS did not install jq.

• Without jq installed, several scripts which parse/modify json files fail to be created/updated, and tar1090 functionality which rely on these json files fails to load/run correctly (e.g., pTracks)
• Failures, and error messages about jq being unavailable, can be observed via journalctl
• Manually installing jq resolved the errors

jq not being installed as part of the normal install process appears to be due to an omitted trailing slash when specifying the string to pass into read (the trailing token is required to denote the end of the last item).

This pull request inserts that trailing slash.

For reference/convenience, these are the relevant lines within install.sh.

## https://github.com/wiedehopf/tar1090/blob/994d4ee08c6c9749a156c5b1a88b83e4b85b6c73/install.sh#L32C1-L34
# terminate with /
command_package="git git/jq jq"
packages=()

Test script
To test/validate this, here is a slightly tweaked copy of the script which allows for toggling between the slash being present or not and the each branch of the if to be printed to the console.

# terminate with /
command_package="git git/jq jq"
#command_package="git git/jq jq/"
packages=()

while read -r -d '/' CMD PKG
do
    if ! command -v "$CMD" &>/dev/null
    then
        echo "command $CMD not found, will try to install package $PKG"
        packages+=("$PKG")
    else
        echo "command $CMD found, package $PKG not required"
        true
    fi
done < <(echo "$command_package")

Terminal output
Note that without the trailing slash, jq is neither required nor found to be absent (meaning that it failed to be read).

pi@raspberry:~ $ ./script--no_trailing_slash.sh
command git found, package git not required

pi@raspberry:~ $ ./script--trailing_slash.sh
command git found, package git not required
command jq not found, will try to install package jq

pi@raspberry:~ $

[mpentler]

I think I have also had this but will confirm off a fresh install of raspbian lite + readsb + tar1090 tomorrow.