66-which is a portable which command that checks if a command exists and is executable in PATH or at specified path. It behaves slightly different then the GNU which command.
66-which [ -h ] [ -q | -a ] command(s)
This tool expect to find valid command name or path, it will check if they exists and are executable by the current user.
It parse PATH for valid entries, applying a substitution of each entry with its realpath and emilinating duplicates.
It parses that command given checking if it is a path or a name.
It prints each command found with the first PATH entry, otherwise it print an error. By passing the -a option, it searches and print command with all the PATH entries, even if it been already found.
-h : prints this help.
-a : prints all. Search and print the command using all the PATH entries, even after the command has already been found.
-q : quiet. Do not print anything on stdout.
Search for a command by using its name:
$ 66-which 66-echo
/usr/bin/66-echo
Check for a command by using its path:
$ 66-which /usr/bin/66-echo
/usr/bin/66-echo
Usage of 66-which in a script:
#!/usr/bin/execlineb -P
if { 66-which -q vgchange }
vgchange -ay
66-which need at least one valid entry in PATH that exists on the system. 66-which is often used on critical scripts, like the ones booting the system, so it’s important to check if PATH contains valid entries for the current system.
66-which correctly handle the tilde ~ character for paths. Beware that same shell, like bash, replaces this character with the current user home path. To pass the correct string to 66-which, containing the tilde character, use quoting like this: 66-which '~/.bin/gvr'.