How to remove date from filename

[Joe Sullivan]

i have a daily file with a name of pdsptmbr_MMDD_a.fdr and I need to change it to
pdstmbr_a.fdr.

The tricky part is that the MMDD on the filename is the previous day's date....

For example file create on July 17 would have the name of pdsptmbr_0716_a.fdr

Thanks for your time.....

[saravanan08 · Accepted solution]

Hi Joe,

i m not able to get your question clearly..

anyway

if u want to change the name of yesterday's file to pdstmbr_a.fdr is easy.

mv pdsptmbr_[0-1][0-9][0-3][0-9]_d.fdr pdstmbr_a.fdr

this will change the name of the file with any date to pdstmbr_a.fdr

but you have to move the file which created today to some other folder then only you can create another one file with the same name rommorow.

[James R. Ferguson]

Hi Joe:

Perl makes this easy.

# cat .mknewname
#!/usr/bin/perl
use strict;
use warnings;
use Time::Local;
my $oldname = shift or die "Filename expected\n";
my ( $first, $mon, $day, $last, $newname );
if ( $oldname =~ m{(.+_)(\d\d)(\d\d)(_.+)} ) {
$first = $1;
$mon = $2;
$day = $3;
$last = $4;
}
my $year = (localtime)[5];
my $epoch = timelocal( 0, 0, 0, $day, $mon - 1, $year ) - ( 60 * 60 * 24 );
( $day, $mon ) = ( localtime($epoch) )[ 3, 4 ];
printf "%s%02d%02d%s\n", $first, $mon + 1, $day, $last;
1;

...

Run as:

# ./mknewname pdsptmbr_0717_a.fdr
pdsptmbr_0716_a.fdr

The script formulates yesterday's date from what it finds in the filename passed. Transitions accross month boundries are handled.

# ./mknewname pdsptmbr_0301_a.fdr
pdsptmbr_0228_a.fdr

...which would be 0229 if the current year was a leap year.

Regards!

...JRF...

[Steven Schweda]

> i have a daily file [...]

If you create one file like this per day, and
you rename it each day, then who cares what's
between the underscores?

bash$ echo 'pdsptmbr_0716_a.fdr' | sed -e 's/_.*_/_/'
pdsptmbr_a.fdr


> i m not able to get your question clearly..

A clearer explanation of why a very simple
solution is inadequate might be nice.

[James R. Ferguson]

Hi (again) Joe:

Duh, I forgot to add the actual rename of your file. This version corrects that:

# cat ./myrename
#!/usr/bin/perl
use strict;
use warnings;
use Time::Local;
my $oldname = shift or die "Filename expected\n";
my ( $first, $mon, $day, $last, $newname );
if ( $oldname =~ m{(.+_)(\d\d)(\d\d)(_.+)} ) {
( $first, $mon, $day, $last ) = ( $1, $2, $3, $4 );
}
else {
die "Filename format missing '_MMDD_'\n";
}
my $year = (localtime)[5];
my $epoch = timelocal( 0, 0, 0, $day, $mon - 1, $year ) - ( 60 * 60 * 24 );
( $day, $mon ) = ( localtime($epoch) )[ 3, 4 ];
$newname = sprintf "%s%02d%02d%s", $first, $mon + 1, $day, $last;
die "Can't rename '$oldname'\n" unless rename($oldname, $newname);
1;

...now simply run:

# ./myrename pdsptmbr_0717_a.fdr

...which renames 'pdsptmbr_0717_a.fdr' to ' pdsptmbr_0716_a.fdr'.

Regards!

...JRF...