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From: roberto@blaise.ibp.fr (Ollivier ROBERT)
Message-Id: <9501271934.AA17198@blaise.ibp.fr>
Subject: Re: shell trick?
To: dgy@seagull.rtd.com (Don Yuniskis)
Date: Fri, 27 Jan 1995 20:34:11 +0100 (MET)
Cc: freebsd-hackers@freefall.cdrom.com
In-Reply-To: <199501271814.LAA21622@seagull.rtd.com> from "Don Yuniskis" at Jan 27, 95 11:14:06 am
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>     How can I, in a shell script, read lines from a file, expand any
> environment variables referenced therein and write results to another
> file?

This not a real answer but you should really do this kind of things
in perl... Its build-in eval function is great for this. You can create
variables on the fly with new names, and so on. For example I read my
new account configuration file and create variables named $conf_<something>
with that :

sub read_config_file
{
    open (CONFIG, "$config") || die "Can't open $config.\n";
    LOOP: while (<CONFIG>)
    {
        next if (/^#/o);        # ignore comments
        next if (/^$/o);        # ignore blank lines
        next if (/^[ \t]*$/o);  # ignore lines with blanks and/or tabs
        chop;
        m#^([a-z0-9_]*)\s*=\s*(.+)$#;
        eval "\$conf_$1 = \"$2\";";
    }
}

if the configuration file has :

def_shell = /bin/tcsh

then $conf_def_shell will have "/bin/tcsh" as value. Neat.
-- 
Ollivier ROBERT     -=- The daemon is FREE! -=-     roberto@FreeBSD.ORG
   FreeBSD keltia 2.1.0-Development #18: Thu Jan 26 22:22:16 MET 1995