AWK script that gets certificate expiration info from PEM-format certificate data

cert_expire.awk

#!/usr/bin/env awk -f

# Processes PEM output to print certificate expiration information.
#
# Example:  Print expiration dates for all certificates on macOS
#
#   security find-certificate -a -p | awk -f cert_expire.awk
#
# Example:  Print expiration dates for all "iPhone Developer" certificates on macOS
#
#   security find-certificate -a -c "iPhone Developer:" -p | awk -f cert_expire.awk

BEGIN {
    formatter = "/usr/bin/openssl x509 -noout -subject -startdate -enddate"
}

/BEGIN CERTIFICATE/, /END CERTIFICATE/ { print | formatter }
/END CERTIFICATE/                      { close(formatter); print "----" }