From 3328ccd1174b3d6161d67fdb13a5be4e42808269 Mon Sep 17 00:00:00 2001
From: Michael Mikonos <127171689+mknos@users.noreply.github.com>
Date: Wed, 15 Nov 2023 12:37:14 +0800
Subject: [PATCH] expand: read stdin

* POD text mentions that reading standard input is supported
* Behave like OpenBSD expand: stdin is implied if no files are given
* Remove POD text specific to unexpand; doesn't belong here
* Now the following are equivalent on my system...

cat ar | perl expand - | md5sum
cat ar | perl expand | md5sum
perl expand ar | md5sum
---
 bin/expand | 25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/bin/expand b/bin/expand
index a6ebd1c1..8717b3aa 100755
--- a/bin/expand
+++ b/bin/expand
@@ -41,7 +41,6 @@ EOF
     exit $_[0];
 }
 
-usage(1) unless scalar @ARGV > 0;
 usage(0) if grep /^-h$/, @ARGV;
 
 # at most one argument
@@ -114,6 +113,9 @@ for my $file (@files) {
     close IN;
 
 }
+unless (@files) {
+    do_expand <STDIN>;
+}
 
 __END__
 
@@ -125,9 +127,6 @@ expand - convert tabs to spaces
 
 expand [B<-h>] [B<-tabstop>] [B<-tab1, tab2, ...>] [B<file> ...]
 
-unexpand [B<-h>] [B<-a>] [B<-tabstop>] [B<-tab1, tab2, ...>]
-[B<file> ...]
-
 =head1 DESCRIPTION
 
 I<expand> processes the named files or the standard input writing the
@@ -140,10 +139,7 @@ If a single B<tabstop> argument is given, tabs are set B<tabstop> spaces
 apart instead of the default 8.  If multiple tabstops are given then
 the tabs are set at those specific columns.
 
-I<unexpand> puts tabs back into the data from the standard input or the
-named files and writes the result on the standard output.
-
-Option (with I<expand> and I<unexpand>):
+=head1 OPTIONS
 
 =over 4
 
@@ -153,19 +149,6 @@ Print a usage message and exit with a status code indicating success.
 
 =back
 
-Option (with I<unexpand> only):
-
-=over 4
-
-=item -a
-
-By default, only leading blanks and tabs are reconverted to maximal
-strings of tabs.  If the B<-a> option is given, tabs are inserted
-whenever they would compress the resultant file by replacing two or
-more characters.
-
-=back
-
 =head1 AUTHOR
 
 =for html