OK so I lied (it was just a little one!) It really uses the abortive GNU regex syntax that is just different enough from Perl to s!+t you if you really know perl REs.....it is like grep. My usual greps are called re and re! linked into /usr/bin. They look like:
[root@devel3 root]# cat /usr/bin/re
#!/usr/bin/perl
die "Usage re [RE]\nFull Perl grep on STDIN\n" unless @ARGV == 1;
my $re = qr/$ARGV[0]/;
while(<STDIN>) {
print if m/$re/;
}
[root@devel3 root]# cat /usr/bin/re!
#!/usr/bin/perl
die "Usage re [RE]\nFull Perl grep on STDIN\n" unless @ARGV == 1;
my $re = qr/$ARGV[0]/;
while(<STDIN>) {
print if ! m/$re/;
}
[root@devel3 root]# cat some.file | re "some perl re"
| 