commandline tool to batch combine pdf files in current directory, using ghostscript

pdfmerge

#!/bin/bash
#
# PDF Combiner
# Combines all files ending in .pdf in current directory
# cc0 Lee2sman 2016
#
# DEPENDENCIES: gs
# USAGE: ./pdfmerge output.pdf
# Make executable and put this in your PATH to be able to run it with pdfmerge output.pdf

hash gs &> /dev/null
if [ $? -eq 1 ]	 #Checks to see if ghostscript is installed
   then
   echo >&2 "gs (ghostscript) must be installed to use pdfmerge."
   echo "On Mac: brew install gs"
   echo "More info at ghostscript.com/"
   exit 1
elif [ $# -eq 0 ] #Exits if missing output name
then
   echo "No output specified. USAGE: pdfmerge output.pdf"
   exit 1
else
   gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=$1 *.pdf
fi