First, a couple nitpicks:
- You have a comment saying "read stdin and any/all files passed as parameters..." Actually, it should say "or" instead of "and" -- the while(<>) reads either from file names given on the command line, or from STDIN, not both.
- If you think you need to do print or die $! at all, you should do it on every print statement. (But you probably don't need to do it at all. When a print to STDOUT fails, you either don't need to be told, or else you'll get other error messages anyway.)
- Doing print "" is a noisy way of doing nothing at all.
All that aside, I think the device you're looking for is the "look-around" assertions in a regex. Here's a slightly modified version of your code (because sometimes I can't help but change things), with the relevant bits added in the final "else" block:
#!/usr/bin/perl
use strict;
use warnings;
my @G1x_replace = (
"M104 S0 ; laser off\n",
"M400 ; wait for moves to finish\nM104 S100 ; laser on\n",
);
while (<DATA>) {
if ( /G1([01])/ ) {
print $G1x_replace[ $1 ];
}
elsif ( /G92|M190/ ) {
next;
}
else {
s/(?<=G1 Z)(?=\d)/-/g; # look-behind and look-ahead to insert
+ "-"
s/E[\d.]+ //g; # no look-around needed, just delete s
+tuff
print;
}
}
__DATA__
G92 E0 ; want to remove all G92 lines (works now)
T1
G1 Z0.050 F7800.000
G10 ; retract
G92 E0
G1 Z0.150 F7800.000
G1 X14.725 Y-8.975 F7800.000
G1 Z0.050 F7800.000
G11 ; unretract
G92 E0
G1 X14.725 Y8.975 E0.01465 F120.000
G10 ; retract
G92 E0
G1 Z0.150 F7800.000
G1 X-9.585 Y-0.615 F7800.000
G1 Z0.050 F7800.000
G11 ; unretract
G92 E0