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wodow
Asked: 2010-11-24 03:48:35 +0800 CST

Split command equivalent/replacement that gives total count of pieces/parts?

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The standard split command on Unix/Linux allows you to split files into fixed size pieces in terms of bytes or lines, with the output file names suffixed with letters or numbers (e.g. PREFIXaa, PREFIXab, ... or PREFIX1, PREFIX2, ...)

However, it's not clear from the output names alone how many pieces there should be.

Is there a standard tool that will do this, i.e. outputting to e.g. PREFIX1of4, PREFIX2of4... or similar? Or is this a job for Perl (i.e. I find a Perl script).

Thanks!

Wodow

linux unix

2 Answers

  1. Best Answer

    if you need to fully identify the "piece number" from the generated "piece files" names you can use "-d" and have the suffix argument to be a directory name where the "piece files" should be generated. Using "-a" you can specify the number of digits to be used to generate the suffix names.

    example: split the file "cfg.pm", 3 lines per output file; use 3 digits for the generated suffixes (making sure the name space isn't exhausted); use number-only suffixes; trick split to generate digit-only file names by specifying a directory as a prefix

    mkdir ./s
split -a 3 -l 3 -d cfg.pm s/

    after that,

    ls s | tail -1

    will implicitly give you the number of generated files

    ls s|tail -1
414
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  2. Picking up from adirau's answer:

    If your system has the Perl script called rename (and it's a version that will support doing this) you can rename your files so that each number is incremented by one and have a prefix and a suffix:

    count=$(($(ls s | tail -n 1) + 1))
rename "my \$n=sprintf(\"%03d\", \$_+1); my \$c=sprintf(\"%03d\", $count); s/.*/prefix\${n}of\${c}/" *

    This would rename the files from:

    000
001
002

    to:

    prefix001of003
prefix002of003
prefix003of003

    This is the bulk of that Perl script, by the way:

    use strict;

use Getopt::Long;
Getopt::Long::Configure('bundling');

my ($verbose, $no_act, $force, $op);

die "Usage: rename [-v] [-n] [-f] perlexpr [filenames]\n"
    unless GetOptions(
        'v|verbose' => \$verbose,
        'n|no-act'  => \$no_act,
        'f|force'   => \$force,
    ) and $op = shift;

$verbose++ if $no_act;

if (!@ARGV) {
    print "reading filenames from STDIN\n" if $verbose;
    @ARGV = <STDIN>;
    chop(@ARGV);
}
for (@ARGV) {
    my $was = $_;
    eval $op;
    die $@ if $@;
    next if $was eq $_; # ignore quietly
    if (-e $_ and !$force)
    {
        warn  "$was not renamed: $_ already exists\n";
    }
    elsif ($no_act or rename $was, $_)
    {
        print "$was renamed as $_\n" if $verbose;
    }
    else
    {
        warn  "Can't rename $was $_: $!\n";
    }
}
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