Helper script to determine if a given list of software is installed and available on the system.

installed.sh

#/usr/bin/env bash

# Helper script to determine if a given list of software is installed and available on the system. 
# The script will fail and output the missing software in case a software can not be found.
#
# Author: Patrick Henninger <privat@skyraptor.eu>
# License: GPLv3
# Examples:
# ./installed.sh "pv rsync vim" && echo "Everything is installed"
# ...
#
# if ! installed.sh "pv rsync vim"; then#
# ...
#

# Configure
LIST="$@"
MISSING=()

function isInstalled() {
  local SOFTWARE="$1"
  
  # Check if SOFTWARE is installed
  if command -v $SOFTWARE &> /dev/null; then
    return 0
  else
    return 1
  fi
}

# Iterate over provided software LIST
for ITEM in $LIST; do
  # Check if the current ITEM is installed and available on this machine
  if ! isInstalled "$ITEM"; then
    # ITEM is not available, add it to the MISSING array
    MISSING+=("$ITEM")
  fi
done

# Check and fail in case we have missing software
if [ ${#MISSING[@]} -eq 0 ]; then
  # No missing software, end execution with success
  exit 0
else
  # Output all the missing software 
  echo "$MISSING"
  
  # End execution with error
  exit 1
fi