Very Computer

by **m_stiefenho..** » Fri, 08 Sep 2000 20:19:41

I want to match piped lines from stdin against a
regular expression. As far as I know I can't use
expr, because the two arguments must be provided
as string and you can't use a hyphen as
substitute for stdin...

Does anybody know a workaround for this?

regards
Marek

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by **Vilmos Sot** » Sat, 09 Sep 2000 00:38:50

> I want to match piped lines from stdin against a
> regular expression. As far as I know I can't use
> expr, because the two arguments must be provided
> as string and you can't use a hyphen as
> substitute for stdin...

It is not clear what you want. Maybe this?

echo Hello world | grep '[Hh]ello'

^ ^
will be stdin regexp

Vilmos

by **Andrew N. McGuir** » Sun, 10 Sep 2000 15:16:18

On Thu, 7 Sep 2000, Vilmos Soti quoth:

~~ Date: Thu, 07 Sep 2000 15:38:50 GMT

~~ Newsgroups: comp.os.linux.misc
~~ Subject: Re: regexp on stdin
~~
~~
~~ > I want to match piped lines from stdin against a
~~ > regular expression. As far as I know I can't use
~~ > expr, because the two arguments must be provided
~~ > as string and you can't use a hyphen as
~~ > substitute for stdin...
~~
~~ It is not clear what you want. Maybe this?
~~
~~ echo Hello world | grep '[Hh]ello'

Use Perl:

echo hello, world | perl -wne 'print if /[Hh]ello/'

I think you will find Perl's regular expressions to be more
powerful than most.

anm
--
BEGIN{ $^W = 0 }; $\ = $/; $$_ = $_ for qw~just another perl hacker~;
my $J = sub { return \$just }; my $A = sub { return \$another };
my $P = sub { return \$perl }; my $H = sub { return \$hacker };
print map ucfirst() . " " => ${&$J()}, ${&$A()}, ${&$P()}, ${&$H()};