Example:

$ ../gnu/src/kill --version | head -n1
kill (GNU coreutils) 9.5
$ ../gnu/src/kill -l SIGUSR1 SIGUSR2
10
12
$ cargo run --all-features kill -l SIGUSR1 SIGUSR2
10
$

Note that the bash built-in kill also supports querying multiple names at the same time, but the Debian default binary (procps-ng 4.0.4) does not.

More issues found while checking #6201

• Signal names in all cases, i.e. SIGUSR1 vs. sIgUsR1: Moved to kill: signal names only understood in uppercase, should accept all casings #6217
• Missing RTMAX/RTMIN on Linux: Moved to kill: missing RTMAX/RTMIN on Linux #6218
• Table (-L) format is wrong: Moved to kill: Table output (-L) format is wrong #6219