Re: umask has no man page?

[Alexis <flexibeast@gmail.com>]

Joe Pfeiffer writes:

> The underlying problem is that umask isn't a standalone command, it's a
> shell builtin.  So if you look at the bash manpage you can find the
> (very terse) documention; of course, there's no hint anywhere that you
> should do that.  Just as for (looking at some other builtins) ulimit,
> unalias, unset....

It seems to me a simple Perl script might do the trick here? For
example, imagine a script called 'dhelp':

--- BEGIN ---
#!/usr/bin/perl

use strict;
use warnings;
use Term::ReadKey;

my $shell = $ENV{'SHELL'};
my $cmd = $ARGV[0];

open(my $fh, '-|', "$shell -c 'type $cmd'")
  or die "Couldn't start $shell: $!";

while (<$fh>) {
    if (/builtin/) {
        print "$cmd is a $shell builtin; press any key for $shell man page ....\n";
        ReadMode 'cbreak';
        my $key = ReadKey(0);
        ReadMode 'normal';
        system('man', $shell);
    } elsif (/alias/) {
        print "$_\n";
    } elsif (/\//) {
        system('man', $cmd);
    }
}
--- END ---

Then the user could type e.g.:

$ dhelp umask

and get told it's a builtin before being sent to the shell man page, or
could type:

$ dhelp whoami

and be sent straight to the man page for whoami(1).

Obviously the above needs to proper input and error handling, and
handling of the different forms the output of 'type' can take in
different shells, but wouldn't something like the above be easiest for
maintainers, and useful for end-users?


Alexis.