diff options
Diffstat (limited to 'lib/dotsh.pl.art')
| -rw-r--r-- | lib/dotsh.pl.art | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/lib/dotsh.pl.art b/lib/dotsh.pl.art new file mode 100644 index 0000000000..4f0f188e3c --- /dev/null +++ b/lib/dotsh.pl.art @@ -0,0 +1,154 @@ +Article 19995 of comp.lang.perl: +Newsgroups: comp.lang.perl +Path: netlabs!news.cerf.net!mvb.saic.com!MathWorks.Com!europa.eng.gtefsd.com!howland.reston.ans.net!news.ans.net!malgudi.oar.net!chemabs!skf26 +From: skf26@cas.org (Scott Frost) +Subject: HOW TO source shell scripts into Perl +Message-ID: <1994Mar21.191518.11636@chemabs.uucp> +Followup-To: scott.frost@cas.org +Keywords: Shell, Source, Dot +Sender: usenet@chemabs.uucp +Organization: Chemical Abstracts Service +Date: Mon, 21 Mar 1994 19:15:18 GMT +Lines: 139 + +A few days ago I posted a request for information on how to source +a shell script into a perl script. In general, the responses indicated that +it could not be done (although one came pretty close to the actual solution). + +A fellow staff member (who I was posting the request for) wasn't satisfied with +the response and came up with a way. + +Before I indicate how he solved the problem, let me suggest some alternative +methods of resolving this issue, + + 1. Hard code the environment variables directly in your PERL script. This + is easy but unreliable. System administrators could change the + production shell script environment variables and your PERL script would + be hosed. + + 2. Create a shell wrapper that dots the shell script into your current + environment and then invoke your perl script. This approach is easy + to do, fairly full proof, but an affront to serious PERL programmers + who believe PERL is God's gift to man (or at least Larry's :-) ). + +Chuck's solution involves running the script in the appropriate shell +environment, dumping the shell's environment variables to a file, and then +reading the environment variables into PERL's environment. + +It supports ksh, sh, csh, and zsh shells. It'll look at the first line of +the file to be executed to determine the shell to run it under, if not found, +it'll look at the SHELL environment variable. If the shell is not one of the +four listed, it'll warn you and attempt to run the shell script under /bin/sh. + + A typical usage might look like this, + #!/usr/bin/perl + + # Make sure dotsh.pl is placed in your /usr/perl/lib + require "dotsh.pl"; + + print "SHELL_ENV_VAR = $SHELL_ENV_VAR\n" ; + &dotsh('/tmp/foo') ; # script to run + print "SHELL_ENV_VAR = $SHELL_ENV_VAR\n" ; + + /tmp/foo looks like this: + #!/bin/ksh + export SHELL_ENV_VAR="hi mom" + +The actual dotsh.pl script follows (BTW, this is now public domain): +# +# @(#)dotsh.pl 03/19/94 +# +# Author: Charles Collins +# +# Description: +# This routine takes a shell script and 'dots' it into the current perl +# environment. This makes it possible to use existing system scripts +# to alter environment variables on the fly. +# +# Usage: +# &dotsh ('ShellScript', 'DependentVariable(s)'); +# +# where +# +# 'ShellScript' is the full name of the shell script to be dotted +# +# 'DependentVariable(s)' is an optional list of shell variables in the +# form VARIABLE=VALUE,VARIABLE=VALUE,... that 'ShellScript' is +# dependent upon. These variables MUST be defined using shell syntax. +# +# Example: +# &dotsh ('/tmp/foo', 'arg1'); +# &dotsh ('/tmp/foo'); +# &dotsh ('/tmp/foo arg1 ... argN'); +# +sub dotsh { + local(@sh) = @_; + local($tmp,$key,$shell,*dotsh,$command,$args,$vars) = ''; + $dotsh = shift(@sh); + @dotsh = split (/\s/, $dotsh); + $command = shift (@dotsh); + $args = join (" ", @dotsh); + $vars = join ("\n", @sh); + open (_SH_ENV, "$command") || die "Could not open $dotsh!\n"; + chop($_ = <_SH_ENV>); + $shell = "$1 -c" if ($_ =~ /^\#\!\s*(\S+(\/sh|\/ksh|\/zsh|\/csh))\s*$/); + close (_SH_ENV); + if (!$shell) { + if ($ENV{'SHELL'} =~ /\/sh$|\/ksh$|\/zsh$|\/csh$/) { + $shell = "$ENV{'SHELL'} -c"; + } else { + print "SHELL not recognized!\nUsing /bin/sh...\n"; + $shell = "/bin/sh -c"; + } + } + if (length($vars) > 0) { + system "$shell \"$vars;. $command $args; set > /tmp/_sh_env$$\""; + } else { + system "$shell \". $command $args; set > /tmp/_sh_env$$\""; + } + + open (_SH_ENV, "/tmp/_sh_env$$") || die "Could not open /tmp/_sh_env$$!\n"; + while (<_SH_ENV>) { + chop; + /=/; + $ENV{$`} = $'; + } + close (_SH_ENV); + system "rm -f /tmp/_sh_env$$"; + + foreach $key (keys(ENV)) { + $tmp .= "\$$key = \$ENV{'$key'};" if $key =~ /^[A-Za-z]\w*$/; + } + eval $tmp; +} +1; + + + + + + + + + + + + + + + + + + + + + + + + + + +-- +Scott K. Frost INET: scott.frost@cas.org + + |