which

Question 1

which

Answer 1

which returns the pathnames of the files (or links) which would be executed in the current environment, had its arguments been given as commands in a strictly POSIX-conformant shell.

Question 2

which -a

Answer 2

-a, Print all matching pathnames of each argument.

Exit Statuses

0 If all specified commands are found and executable

1 If one or more specified commands is nonexistent or not executable

2 If an invalid option is specified.