What does the leading dash in process cmdline mean?

I noticed a process taking full CPU on my linux server, of which the COMMAND column from top -c is -bash.

cat /proc/<pid>/cmdline shows -bash too.

What does the leading dash mean?

More info: I don't know if it's relevant, /proc/<pid>/exe -> /bin/bash (deleted)


The dash is only relevant to bash (and other shells). It only means that the shell is a login shell.