Create self-signed certificate script

ssc.sh

#!/bin/bash

usage() { 
   echo "Generates a self-signed certificate."
   echo
   echo "Usage: $0 [-h] [-d] [-c <county>] [-s <state>] [-l <city>] [-o] [-n <common_name>] [-f] [<path>]"
   echo -e "options:"
   echo -e "\tpath  The output path where the key and crt files are generated."
   echo -e "\t-c    The certificate country. E.g. DE or US"
   echo -e "\t-s    The certificate state."
   echo -e "\t-l    The certificate city (location)."
   echo -e "\t-o    The certificate organization."
   echo -e "\t-n    The certificate CN. Default is localhost"
   echo -e "\t-v    Validity in days. Default is 365."
   echo -e "\t-f    Output name. Default is server"
   echo -e "\t-d    Dry run - show command."
   echo -e "\t-h    Print this help."
   echo
   exit 1; 
}

dryRun=false
subj=""

while getopts ":c:s:l:n:o:f:v:dh" o; do
    case "${o}" in
        h)
            usage
            ;;
        c)
            subj="${subj}/C=${OPTARG}"
            ;;
        s)
            subj="${subj}/ST=${OPTARG}"
            ;;
        l)
            subj="${subj}/L=${OPTARG}"
            ;;
        o)
            subj="${subj}/O=${OPTARG}"
            ;;
        n)
            cn="${OPTARG}"
            ;;
        v)
            validDays="${OPTARG}"
            ;;
        f)
            outname="${OPTARG}"
            ;;
        d)
            dryRun=true
            ;;
        *)
            echo "ERROR: Invalid option -$OPTARG"
            usage
            ;;
    esac
done
shift $((OPTIND-1))

subj="${subj}/CN=${cn:-localhost}"
outpath="${1:-.}" # current directory if undefined
outfilename="${outname:-server}" # server if undefined

isCygwin=false
case "$(uname -s)" in
   CYGWIN*|MINGW32*|MSYS*|MINGW*)
     isCygwin=true
     ;;
esac

cygwinPatch=""
if [ "${isCygwin}" == true ]; then
    cygwinPatch="export MSYS_NO_PATHCONV=1; ";
fi

cmd="cd \"${outpath}\"; ${cygwinPatch}openssl req -new -newkey rsa:4096 -days ${validDays:-365} -nodes -x509 -subj \"${subj}\" -keyout \"${outfilename}.key\" -out \"${outfilename}.crt\""

if [ "$dryRun" = true ]; then
    echo $cmd
else
    bash -c "$cmd"
fi

Just running

./ssc.sh

will generate a self-signed certificate in the current working directory that is valid for 1 year:

./server,key
./server.crt