File Manipulation: Scripting Question

Question

I have a script which connects to database and gets all records which statisfy the query. These record results are files present on a server, so now I have a text file which has all file names in it.

I want a script which would know:

1. What is the size of each file in the output.txt file?
2. What is the total size of all the files present in that text file?

Update: I would like to know how can I achieve my task using Perl programming language, any inputs would be highly appreciated.

Note: I do not have any specific language constraint, it could be either Perl or Python scripting language which I can run from the Unix prompt. Currently I am using the bash shell and have sh and py script. How can this be done?

My scripts:

#!/usr/bin/ksh
export ORACLE_HOME=database specific details
export PATH=$ORACLE_HOME/bin:path information
sqlplus database server information<<EOF
SET HEADING OFF
SET ECHO OFF
SET PAGESIZE 0
SET LINESIZE 1000
SPOOL output.txt
select * from my table_name;
SPOOL OFF
EOF

I know du -h would be the command which I should be using but I am not sure how should my script be, I have tried something in python. I am totally new to Python and it's my first time effort.

Here it is:

import os

folderpath='folder_path'
file=open('output file which has all listing of query result','r')

for line in file:
 filename=line.strip()
 filename=filename.replace(' ', '\ ')
 fullpath=folderpath+filename
# print (fullpath)
 os.system('du -h '+fullpath)

File names in the output text file for example are like: 007_009_Bond Is Here_009_Yippie.doc

Any guidance would be highly appreciated.

Update:

1. How can I move all the files which are present in output.txt file to some other folder location using Perl ?
2. After doing step1, how can I delete all the files which are present in output.txt file ?

Any suggestions would be highly appreciated.

Answer 1

In perl, the -s filetest operator is probaby what you want.

use strict;
use warnings;
use File::Copy;

my $folderpath = 'the_path';
my $destination = 'path/to/destination/directory';
open my $IN, '<', 'path/to/infile';
my $total;
while (<$IN>) {
    chomp;
    my $size = -s "$folderpath/$_";
    print "$_ => $size\n";
    $total += $size;
    move("$folderpath/$_", "$destination/$_") or die "Error when moving: $!";
}
print "Total => $total\n";

Note that -s gives size in bytes not blocks like du.

On further investigation, perl's -s is equivalent to du -b. You should probably read the man pages on your specific du to make sure that you are actually measuring what you intend to measure.

If you really want the du values, change the assignment to $size above to:

my ($size) = split(' ', `du "$folderpath/$_"`);