[Linux-users] converting bash scripts to perl

[Bill Campbell]

On Sat, Aug 25, 2007, Lonni J Friedman wrote:
>Anyone have any experience converting a large number of bash shell
>scripts over to perl?

The attached script might be used as a first cut.  I wrote it
years ago to parse simple shell scripts to perl, mostly scripts
which set environment variables.

It might be easier to convert to python as simple assignment
statments will work in a large percentage of the cases.

This script will require a bit of cleanup as it's calling the
OpenPKG instance of perl on my mail server.

Bill
--
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URL: http://www.celestial.com/  PO Box 820; 6641 E. Mercer Way
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                -- Robert Heinlein
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#!/csrel25/bin/perl
eval ' exec /csrel25/bin/perl -S $0 "$@" '
	if $running_under_some_shell;
	shift if(join("", @ARGV) eq ""); # Xenix Kludge

# $Header: /vol/cscvs/lbin/shtoperl,v 1.6 1995/12/24 01:35:56 bill Exp $
# $Date: 1995/12/24 01:35:56 $
# @(#) $Id: shtoperl,v 1.6 1995/12/24 01:35:56 bill Exp $

( $progname = $0 ) =~ s!.*/!!; # save this very early

$USAGE = "
#
#   Usage: $progname [-v] [-d dirctory] file [file...]
#
# Options   Argument    Description
#   -s                  Strip comments
#   -v                  Verbose
#
";

sub usage {
	die join("\n", at _) .
	"\n$USAGE\n";
}

do "getopts.pl";
do "/csrel25/etc/csspath.perl" unless $usr_bin_csspath;

&usage("Invalid Option") unless do Getopts("sv");

$verbose = ( $opt_v ? '-v' : () );

$\ = "\n";	# use newlines as separators.

$double_quotes = '""';
$single_quote = '"';

sub shtoperl {
	local($file_handle) = @_;
	open($file_handle, $file_handle);
	while(<$file_handle>) {
		next if /^:/;
		chop;
		if(/^[\s;]*#/) {
			print unless $opt_s;
			next;
		}
		foreach (split(/;\s/, $_, 9999)) {
			next if ( /^\s*set\s+-x/ );
			if (/^\s*\.\s*(\S+)/) {
				print "# including $1";
				&shtoperl($1);
				next;
			}
			$comment = '';
			if(/#/) {
				($comment = $_) =~ s/[^#]*(\s*#.*)/$1/;
				($pattern = $comment) =~ s/([()])/\\$1/g;
				s/$pattern$//e if $comment;		# strip trailing comment
				s/(\s*)$//;						# trailing white space
				$comment = "$1$comment";
			}
			next if ( $opt_s && /^\s*$/ );
			;# take care of -a in if statements.
			s/\s+-a\s+/ && /g;
			if(/^(\s*)\[(.*)\]\s+&&\s+\{/)	#}
			{
				$leadspace = $1;
				$_ = $2;
				s/-z/!/;
				s/\s+=\s+/ eq /;
				s/\s+!=\s+/ ne /;
				s/""/''/g;
				# s/"//g;
				# s/\$(\S+)/\$ENV{"$1"}/g;
				print "${leadspace}if ($_) \{";	#}
				next;
			}
			s/;$//;
			s/(\s*)([^=]*)=(.*)/$1\$$2 = "$3";/;
			s/(\s*)export\s*(.*)/$1\$ENV{'$2'} = \$$2;/;
			s/$double_quotes/$single_quote/g;
			s/"''"/''/g;
			s/^(\s*)if\s+test(.*)/$1if( $2 )/;
			s/^(\s*)if\s+-z/$1if !/;
			s/^(\s*)then/$1\{/;
			s/^(\s*)fi/$1}/;
				# the next two lines take care of backtick operators.
			s/"*`"*/`/g;
			s/(\S+\s+\=\s+\S*\`.*`)/chop($1)/g;
			s/^(\s*)unset\s+(\S+)/$1delete \$ENV{'$2'};/;
			print "$_$comment";
		}
	}
	close($file_handle);
}
for (@ARGV) {
	&shtoperl($_);
}