Octal mode translations

Octal mode translations

Posted Aug 2, 2018 20:40 UTC (Thu) by rweikusat2 (subscriber, #117920)
In reply to: The Grumpy Editor's Python 3 experience by rweikusat2
Parent article: The Grumpy Editor's Python 3 experience

BTW,

#!/usr/bin/perl
#

sub usage
{
    print STDERR ("Usage: pchmod <mode arg> <path>+\n");
    exit(1);
}

sub add { $_[0] | $_[1] }
sub clear { $_[0] & ~$_[1] } 
sub set { $_[1] }

sub valid_mode
{
    $_[0] =~ /^([+-])?0?[0-7]{1,3}$/;
}

sub parse_mode
{
    my (@ops, $op, $v);

    for (split(/,/, $_[0])) {
        die("invalid mode $_") unless valid_mode($_);
        
        if (/^([+-])(.*)/) {
            $op = $1 eq '+' ? \&add : \&clear;
            $v = $2;
        } else {
            $op = \&set;
            $v = $_;
        }

        push(@ops, [$op, oct($v)]);
    }

    return @ops;
}

my (@ops, @stat, $m, $rc);

@ARGV > 1 || usage();
@ops = parse_mode(shift);

for (@ARGV) {
    @stat = stat;
    @stat or warn("stat '$_': $!"), next;

    $m = $stat[2];
    $m = $_->[0]($m, $_->[1]) for @ops;
    $rc = chmod($m, $_);
    $rc or warn("chmod '$_': $!");
}

Assuming that's called pchmod, it becomes something like pchmod +511,-2.

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