Appends value(s) onto the given VAR with a delimiter.

add_to_var

#!/usr/bin/env bash

# Appends value(s) onto the given VAR, separated by delim.
# If not specified, delim is $IFS.
# Example: building a list of command-line options
# addto OPTIONS -server -Dfoo=true
# addto OPTIONS -host 127.0.0.1 -port 9999
# addto OPTIONS -debug
# program ${OPTIONS} "$@"

# usage: addto [-d delim] VAR [value*]
addto() {
  local delim=${IFS}
  if [ "$1" = "-d" ]; then
    shift
    delim="$1"
    shift
  fi
  local v=$1; shift
  while [ -n "$1" ]; do
    eval "$v=\${$v:+\${$v}${delim}}\"$1\""
    shift
    done
}