pidof
Linux has this command, but not in macOS, so I write it for you.
Program name is case insensitive by default, pass -S option if you want sensitive match.
USAGE:
./zig-out/bin/pidof [OPTIONS] [--] [program]
OPTIONS:
-s, --single Only return the first matching pid.
-d, --delimiter STRING Delimiter used if more than one PID is shown.(default: )
-S, --strict Case sensitive when matching program name.
-u, --user_only Only show process belonging to current user.
-v, --version Print version.
-h, --help Print help message.