Match acronyms

#/!bin/bash

# Example file containing acronyms
acro_file=$(mktemp)
printf "Foo\nBar\n" > "$acro_file"

# Example file containing server names
server_file=$(mktemp)
printf "FooServer\nBarServer\nBazServer\n" > "$server_file"

sed 's/\(.\{3\}\)/\1\t\1/' "$server_file" | # Prepend server names with first three characters and tab
sort -k1 | # sort based on first column (i.e. acronym)
join - <(sort "$acro_file") | # merge server_file and acro_file based on first column of both inputs
cut -d' ' -f2 # keep only full server name

rm "$acro_file" "$server_file"