finding a file in directory using perl script

Question

I'm trying to develop a perl script that looks through all of the user's directories for a particular file name without the user having to specify the entire pathname to the file.

For example, let's say the file of interest was data.list. It's located in /home/path/directory/project/userabc/data.list. At the command line, normally the user would have to specify the pathname to the file like in order to access it, like so:

cd /home/path/directory/project/userabc/data.list

Instead, I want the user just to have to enter script.pl ABC in the command line, then the Perl script will automatically run and retrieve the information in the data.list. which in my case, is count the number of lines and upload it using curl. the rest is done, just the part where it can automatically locate the file

Answer 1

Even though very feasible in Perl, this looks more appropriate in Bash:

#!/bin/bash

filename=$(find ~ -name "$1" )
wc -l "$filename"
curl .......

The main issue would of course be if you have multiple files data1, say for example /home/user/dir1/data1 and /home/user/dir2/data1. You will need a way to handle that. And how you handle it would depend on your specific situation.

In Perl that would be much more complicated:

#! /usr/bin/perl -w
    eval 'exec /usr/bin/perl -S $0 ${1+"$@"}'
        if 0; #$running_under_some_shell

use strict;

# Import the module File::Find, which will do all the real work
use File::Find ();

# Set the variable $File::Find::dont_use_nlink if you're using AFS,
# since AFS cheats.

# for the convenience of &wanted calls, including -eval statements:
# Here, we "import" specific variables from the File::Find module
# The purpose is to be able to just type '$name' instead of the
# complete '$File::Find::name'.
use vars qw/*name *dir *prune/;
*name   = *File::Find::name;
*dir    = *File::Find::dir;
*prune  = *File::Find::prune;

# We declare the sub here; the content of the sub will be created later.
sub wanted;

#  This is a simple way to get the first argument. There is no 
# checking on validity.
our $filename=$ARGV[0];


# Traverse desired filesystem. /home is the top-directory where we
# start our seach. The sub wanted will be executed for every file 
# we find
File::Find::find({wanted => \&wanted}, '/home');
exit;


sub wanted {
    # Check if the file is our desired filename
    if ( /^$filename\z/) {
        # Open the file, read it and count its lines
        my $lines=0;
        open(my $F,'<',$name) or die "Cannot open $name";
        while (<$F>){ $lines++; }
        print("$name: $lines\n");

        # Your curl command here
    }
}

You will need to look at the argument-parsing, for which I simply used $ARGV[0] and I do dont know what your curl looks like.

A more simple (though not recommended) way would be to abuse Perl as a sort of shell:

#!/usr/bin/perl
#
my $fn=`find /home -name '$ARGV[0]'`;
chomp $fn;
my $wc=`wc -l '$fn'`;
print "$wc\n";
system ("your curl command");

Answer 2

Following code snippet demonstrates one of many ways to achieve desired result.

The code takes one parameter, a word to look for in all subdirectories inside file(s) data.list. And prints out a list of found files in a terminal.

The code utilizes subroutine lookup($dir,$filename,$search) which calls itself recursively once it come across a subdirectory.

The search starts from current working directory (in question was not specified a directory as start point).

use strict;
use warnings;
use feature 'say';

my $search = shift || die "Specify what look for";
my $fname  = 'data.list';

my $found = lookup('.',$fname,$search);

if( @$found ) {
    say for @$found;
} else {
    say 'Not found';
}

exit 0;

sub lookup {
    my $dir    = shift;
    my $fname  = shift;
    my $search = shift;

    my $files;
    my @items = glob("$dir/*");

    for my $item (@items) {
        if( -f $item && $item =~ /\b$fname\b/ ) {
            my $found;
            open my $fh, '<', $item or die $!;
            while( my $line = <$fh> ) {
                $found = 1 if $line =~ /\b$search\b/;
                if( $found ) {
                    push @{$files}, $item;
                    last;
                }
            }
            close $fh;
        }
        if( -d $item ) {
            my $ret = lookup($item,$fname,$search);
            push @{$files}, $_ for @$ret;
        }
    }

    return $files;
}

Run as script.pl search_word

Output sample

./capacitor/data.list
./examples/data.list
./examples/test/data.list

Reference: glob, Perl file test operators