Nice work! I would have done some things differently, but this is very readable.
Two recommendations for reading the file:
- Use the
(z)and(Q)flags so that instead of using tabs to separate the targets, simply quoting each argument works. - Instead of two independent lists, use an associative array with
map[$link]=$target. Then you can check for duplicate links while reading the list.
linksfile=$1
typeset -gA linkmap
while read -r line
do
# -- fields
fields=(${(Q)${(z)line}})
# -- link
link=${(e)~fields[1]}
# -- target
target=${(e)~fields[2]}
# -- check if we've already seen this link
if (( $+linkmap[$link] )); then
echo "'$link' targets both '$linkmap[$link]' and '$target', aborting"
exit 1
fi
if [ -z "$target" ] || [ -z "$link" ]; then
echo "Empty link or target provided, skipping"
continue
fi
linkmap[$link]=$target
done < $linksfile
Then later, you can iterate over each key-value pair:
for link target in "${(@kv)linkmap}"; do
...
done