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Batch file renaming - on identical name, keep only most recent file, based on dates

by Anonymous Monk
on Nov 05, 2019 at 13:43 UTC ( #11108322=perlquestion: print w/replies, xml ) Need Help??

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hello dear Monks, I need to rename many files (~5,000) in a directory. They have the following structure: 8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf and I need to strip off the first 7 numbers (userID and then year-month-day-hour-minute-second). The challenge here is that some of them might actually have the same filename remaining after this operation, like the following example:
8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf 8_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf
So, in this case, I would like to keep only the most recent one. To do this, I can use the following simple code I wrote:
use Date::Parse; $file1 = '2019-3-25T14:40:22'; $file2 = '2019-6-12T22:34:8'; if (str2time( $file1 ) - str2time( $file2 )) { print "$file1 is more recent than $file2\n"; }
after transforming the dates into the above-mentioned command. My problem is, how to go about finding and comparing the ones that actually have the same filename, after stripping out the unnecessary information from the beginning - so that I know which ones I need to compare. any help will be greatly appreciated. Thanks!

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Re: Batch file renaming - on identical name, keep only most recent file, based on dates (updated)
by haukex (Chancellor) on Nov 05, 2019 at 14:39 UTC

    Here's how I might have coded this. Disclaimer: I've only done a small amount of testing on this, use at your own risk!

    #!/usr/bin/env perl use warnings; use strict; use Time::Piece; use File::Spec::Functions qw/ no_upwards catfile /; use Getopt::Long qw/ HelpMessage :config posix_default gnu_compat bundling auto_help /; use Data::Dumper; $Data::Dumper::Quotekeys=0; $Data::Dumper::Useqq=$Data::Dumper::Sortkeys=1; =head1 SYNOPSIS myrename.pl [OPTIONS] PATH OPTIONS: -r | --run - Actually perform actions -v | --verbose - With --run, report actions -q | --quiet - Suppress warning messages -d | --debug - Enable debugging (overrides -v and -q) =cut GetOptions( 'r|run' => \( my $RUN ), 'v|verbose' => \( my $VERBOSE ), 'q|quiet' => \( my $QUIET ), 'd|debug' => \( my $DEBUG ), version => sub { print q$myrename.pl v0.01$,"\n"; exit }, ) or HelpMessage(-exitval=>255); HelpMessage(-exitval=>255) unless @ARGV==1; if ( $DEBUG ) { $VERBOSE=1; $QUIET=0; } my $PATH = $ARGV[0]; print STDERR Data::Dumper->Dump([$PATH],['PATH']) if $DEBUG; opendir my $dh, $PATH or die "$PATH: $!"; my @FILES = sort grep { -f catfile($PATH,$_) } no_upwards readdir $dh; closedir $dh; print STDERR Data::Dumper->Dump([\@FILES],['*FILES']) if $DEBUG; my %files; FILE: for my $origfile (@FILES) { my ($uid,$time,$file) = $origfile =~ /\A(\d+_)((?:\d+_){6})(.+)\z/ or do { warn "No match, skipping $origfile\n" unless $QUIET; next FILE }; print STDERR Data::Dumper->Dump([$uid,$time,$file], [qw/uid time file/]) if $DEBUG; $time = Time::Piece->strptime($time, '%Y_%m_%d_%H_%M_%S_')->epoch; push @{ $files{$file} }, { origfile => $origfile, time=>$time }; } @$_ = sort { $b->{time} <=> $a->{time} } @$_ for values %files; print STDERR Data::Dumper->Dump([\%files],['*files']) if $DEBUG; for my $file (sort keys %files) { my $keep = shift @{ $files{$file} }; my $srcfile = catfile($PATH,$keep->{origfile}); my $dstfile = catfile($PATH,$file); print "Rename $srcfile to $dstfile\n" if !$RUN || $VERBOSE; die "Destination file exists: $dstfile\n" if -e $dstfile; # NOTE: There is a possible race condition between -e and rename if ($RUN) { rename($srcfile, $dstfile) or die "rename($srcfile, $dstfile): $!"; } for my $drop ( @{ $files{$file} } ) { my $dropfile = catfile($PATH,$drop->{origfile}); print "Drop $dropfile\n" if !$RUN || $VERBOSE; if ($RUN) { unlink($dropfile) or die "unlink($dropfile): $!"; } } } warn "This was a dry-run, no actions performed\n" unless $RUN;

    For a set of files ( "2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf", "8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf", "8_2007_5_22_15_34_23_Table_-_2008522_XYZ_W3.pdf", "8_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf" ), the output is:

    No match, skipping 2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf Rename x/8_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf to x/Table_-_ +2007522_XYZ_W3.pdf Drop x/8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf Rename x/8_2007_5_22_15_34_23_Table_-_2008522_XYZ_W3.pdf to x/Table_-_ +2008522_XYZ_W3.pdf

    Update: I guess a few words of explanation would be helpful. First off, note that this loads the entire list of files into memory, but with 5k files, I think that should be fine. Most of the first half of the script is just setting up and reading the list of files from the directory. The interesting stuff happens in the %files hash: it's a hash where the keys are the target filenames, and each value is an array of the original filenames, along with their datetimes parsed into UNIX timestamps (use the --debug switch to see the data structures). This allows me to simply sort each list of files (the @$_ = sort ... step) so that the first element of each array is the latest filename. Then, I loop over all the files again, taking the first element of each array as the file to keep and rename to the target filename, and I delete all the other files. I hope this makes sense, and feel free to ask if anything is unclear. (Note I used core modules only.)

Re: Batch file renaming - on identical name, keep only most recent file, based on dates
by Fletch (Chancellor) on Nov 05, 2019 at 14:12 UTC

    Handwaving fish.

    my @candidate_files = obtain_candidates( ); ## File::Find::Rule, opend +ir/readdir, ... my %seen_files; my @to_delete; for my $file ( @candidate_files ) { ## regex out, use str2date, yadda yadda yadda my( $real_file, $date ) = parse_filename( $file ); if( not exists $seen_files{ $real_file } ) { $seen_files{ $real_file } = [ $file, $date ]; } else { my $prior_date = $seen_files{ $real_file }->[1]; if( $date - $prior_date > 0 ) { $seen_files{ $real_file } = [ $file, $date ]; } else { push @to_delete, $file; } } } process_deletions( @to_delete );

    The cake is a lie.
    The cake is a lie.
    The cake is a lie.

Re: Batch file renaming - on identical name, keep only most recent file, based on dates
by jcb (Chaplain) on Nov 06, 2019 at 02:13 UTC

    That you are stripping off a userID field seems suspicious to me. Are you sure that you want to conflate files from different users?

Re: Batch file renaming - on identical name, keep only most recent file, based on dates
by siberia-man (Monk) on Nov 05, 2019 at 16:41 UTC
Re: Batch file renaming - on identical name, keep only most recent file, based on dates
by Lotus1 (Vicar) on Nov 06, 2019 at 04:55 UTC

    jcb beat me to the point about collisions from different users. (Edit: it's late here and I got things reversed in my head. No need for the reverse for the sort.) Here is a simple solution that works except it will clobber any collisions between users with the user with the lowest highest number. This solution takes a reverse sort of the filenames and then uses File::Copy::move to rename them so that the newest collision file is the last one to be renamed. If you specify what to do by user collisions this could be modified to watch for the user number.

    Perl has a built in rename function but the documentation suggests using File::Copy::move since it is more portable across operating systems.

    use warnings; use strict; use File::Copy; use File::Glob ':glob'; mkdir 'test' unless -d 'test'; #foreach( reverse sort glob( "*_Table_*.pdf" ) ){ foreach( sort glob( "*_Table_*.pdf" ) ){ print "$_\n"; my $newname = $_; $newname =~ s/^[0-9_]+//; print "--$newname\n"; ## using copy for testing. copy $_, "./test/$newname" or print "Error copying <$_> $!\n"; #move $_, "$newname" or print "Error renaming <$_> $!\n"; } __DATA__ test files: 8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf 8_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf 7_2007_5_22_16_35_23_Table_-_2007522_XYZ_W3.pdf 7_2007_5_22_23_36_12_Table_-_2007522_XYZ_W3.pdf output file: Table_-_2007522_XYZ_W3.pdf

    Edit: I forgot to add the program output. Also, I had an extra file in my test files.

    8_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 7_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 7_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 7_2007_12_22_15_34_23_Table_-_20071222_XYZ_W3.pdf --Table_-_20071222_XYZ_W3.pdf

    Edit: updated output without reverse sort.

    7_2007_12_22_15_34_23_Table_-_20071222_XYZ_W3.pdf --Table_-_20071222_XYZ_W3.pdf 7_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 7_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 8_2007_5_22_15_34_23_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf 8_2007_5_22_22_34_12_Table_-_2007522_XYZ_W3.pdf --Table_-_2007522_XYZ_W3.pdf
      sort glob( "*_Table_*.pdf" )

      Unfortunately that doesn't work because it'll incorrectly sort a later datetime of e.g. 2007_10_22_15_34_23 before 2007_9_22_15_34_23.

        I thought of that and wish now I had mentioned it in my writeup. There is no chance of a name collision in that example since the year, month and day are repeated in the new name. For example:

        8_2007_10_22_15_34_23_Table_-_20071022_XYZ_W3.pdf 8_2007_9_22_15_34_23_Table_-_2007922_XYZ_W3.pdf

        The new filenames for these two will be:

        Table_-_20071022_XYZ_W3.pdf Table_-_2007922_XYZ_W3.pdf

        Having the sorting correct only matters among the filenames that start with the same YYYY?MDD dates. The HH_mm_ss format seems to be consistent and therefore sortable with the default sort. I'm assuming that from the limited example data we were given.

Re: Batch file renaming - on identical name, keep only most recent file, based on dates
by Anonymous Monk on Nov 05, 2019 at 14:23 UTC
    Ok, so I brought it here: I first get all the filenames into one text file and then I run the following, on the file:
    use strict; use warnings; use Date::Parse; my @AoA_files=(); open IN, $ARGV[0]; while(<IN>) { my $infile=$_; chomp $infile; if($infile=~/^(\d+)\_(\d+)_(\d+)_(\d+)_(\d+)_(\d+)_(\d+)_(.*)/) { my $uid=$1; my $year=$2; my $month=$3; my $day=$4; my $hour=$5; my $minute=$6; my $second=$7; my $actual_filename=$8; my $timestamp = "$year-$month-$day"."T"."$hour:$minute:$second +"; if ( grep { $_->[1] eq $actual_filename } @AoA_files ) #if fil +ename exists, keep only the most recent one { #compare the timestamps my $existing_timestamp = $_->[0]; my $difference_in_seconds = str2time($timestamp) - str2tim +e($existing_timestamp); if($difference_in_seconds > 0) #current date is newer than + the one in the AoA - use this one { push @AoA_files, [ $timestamp, $actual_filename]; } } else #add it normally to the AoA { push @AoA_files, [ $timestamp, $actual_filename]; } } }
    My idea here is to eventually create a second file with the full filenames that I need to keep. Does that make sense?
      • ALWAYS check the return value from open and show the error: open( ... ) or die qq{Problem opening '$ARGV[0]': $!\n};
      • If you'd use a hash like I suggested rather than an AoA it'd be more efficient; you're doing a linear search over all of your filenames repeatedly whereas a hash can just do exists

      Those nitpicks aside, seeing as that's basically my suggestion above . . . looks sane. (Sanity not guaranteed. Contents may have settled during shipping. Prices may be higher in AK and HI.)

      Edit: tweaked wording of second item slightly. Me no make sense much early morning do.

      The cake is a lie.
      The cake is a lie.
      The cake is a lie.

Re: Batch file renaming - on identical name, keep only most recent file, based on dates
by shadowsong (Pilgrim) on Nov 06, 2019 at 23:02 UTC

    Hi Anon

    Here's another approach

    #!perl -sl use strict; use warnings FATAL => 'all'; my $PATH = "c:/code/test"; my $processed_hash_ref; chdir $PATH; # filetests using relative path opendir DH, "." or die "Couldn't open directory $PATH: $!"; while ($_ = readdir (DH)) { next unless -f $_ && m/^\d_\d{4}_\d\d?_\d\d?_\d\d?_\d\d?_\d\d?_table/i; my $fname = join ('_', (split /_/)[ 7..11 ]); # already seen a more recent file with the name we're # planning to use? skip current file next if defined $processed_hash_ref->{$fname} && $processed_hash_ref->{$fname}->{AGE} < -M _; # file safe to be renamed... for now $processed_hash_ref->{$fname}->{OLDNAME} = $_; $processed_hash_ref->{$fname}->{AGE} = -M _; } closedir DH; # now proceed to rename items map { print "[!] rename $processed_hash_ref->{$_}->{OLDNAME} to $_"; rename $processed_hash_ref->{$_}->{OLDNAME}, $_; } keys %$processed_hash_ref;

    Cheers
    Shadow

      -M _

      I think it's very much worth noting that this relies on the file's modification time being the same as the timestamp in the filename, which is IMHO is pretty risky. For example, if the timestamp in the filename is the time a log file was started, its modification time may very well be much later than that. Or, if the files were copied into this directory from somewhere else, the modification times may be completely unreliable.

        ++, but the timestamp in the original file name doesn't necessarily refer to creation/update of the corresponding file, either.

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