Re: [WOT] sh script to relace chars in #1 w/ chars in #2?

[Erdmut Pfeifer <e.pfeifer@science-computing.de>]

On Fri, Jan 12, 2001 at 10:46:36AM -0800, Kenward Vaughan wrote:
> Hi, 
> 
> I have written about 5 successful low-level scripts to do various things,
> and want to learn more about the ways, but I'm in a time crunch (classes
> are starting next week) and I can't begin to grok what's needed for this.
> I was hoping some kind, (bored?) soul could throw clues this way.. ??  :)

well, whatever I am (kind, bored, ... :), here is another one in Perl
for you to compare with the Python solution already posted:


#!/usr/bin/perl -i.bak
                # if you don't want backup files, use just '-i' instead 

while (<>) {  # for each line in the output file...

    if ($outfile ne $ARGV) {
        # make this 'if' match only once (at the beginning of each file)
        $infile = $outfile = $ARGV;
        # '.pdb' -> '.m3d' for input filename
        $infile =~ s/pdb$/m3d/;
        # open associated input file
        open IN, $infile or die "Cannot open file '$infile'!\n";
        $line = 1;
    }
    $in = <IN>;
    if (/^ATOM/) {
        # extract symbols
        $isym = substr($in, 6, 2);
        $osym = substr($_, 13, 2);
        if ($osym eq 'Du') {
            # replace out-symbol with symbol from infile
            substr($_, 13, 2) = $isym;
        } elsif ($isym ne $osym) {
            # verify the assumption that symbols match if out-symbol is not 'Du'
            print STDERR "Warning: symbols don't match! ($ARGV:$line: '$osym'/'$isym')\n";
        }
    }
    print $_;  # write out
    $line++;   # (line counter for warning msg)
}


The script assumes that you have the same number of leading lines in both
files, as you described (input: '3rd line', output: 'line 3').
In your sketch of the file contents, however, it looks as if there is one
more leading line in the output file. If that's not just a typo, you'd
have to make a small change to the script to make corresponding rows align.
Let me know if you can't figure it out yourself...


Call it like this:

  script <list of .pdb-files to change>

e.g.

  script *.pdb

(where 'script' is the name you choose, of course)
Corresponding input files are assumed to reside in the same directory.
Original output files will be renamed to '*.pdb.bak'.


Enjoy,
Erdmut


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