How can I use perl to delete files matching a regex - regex

Question

Due to a Makefile mistake, I have some fake files in my git repo...
$ ls
=0.1.1 =4.8.0 LICENSE
=0.5.3 =5.2.0 Makefile
=0.6.1 =7.1.0 pyproject.toml
=0.6.1, all_commands.txt README_git_workflow.md
=0.8.1 CHANGES.md README.md
=1.2.0 ciscoconfparse/ requirements.txt
=1.7.0 configs/ sphinx-doc/
=2.0 CONTRIBUTING.md tests/
=2.2.0 deploy_docs.py tutorial/
=22.2.0 dev_tools/ utils/
=22.8.0 do.py
=2.7.0 examples/
$
I tried this, but it seems that there may be some more efficient means to accomplish this task...
# glob "*" will list all files globbed against "*"
foreach my $filename (grep { /\W\d+\.\d+/ } glob "*") {
my $cmd1 = "rm $filename";
`$cmd1`;
}
Question:
I want a remove command that matches against a pcre.
What is a more efficient perl solution to delete the files matching this perl regex: /\W\d+\.\d+/ (example filename: '=0.1.1')?

Answer 1

Fetch a wider set of files and then filter through whatever you want
my #files_to_del = grep { /^\W[0-9]+\.[0-9]+/ and not -d } glob "$dir/*";
I added an anchor (^) so that the regex can only match a string that begins with that pattern, otherwise this can blow away files other than intended. Reconsider what exactly you need.
Altogether perhaps (or see a one-liner below †)
use warnings;
use strict;
use feature 'say';
use File::Glob ':bsd_glob'; # for better glob()
use Cwd qw(cwd); # current-working-directory
my $dir = shift // cwd; # cwd by default, or from input
my $re = qr/^\W[0-9]+\.[0-9]+/;
my #files_to_del = grep { /$re/ and not -d } glob "$dir/*";
say for #files_to_del; # please inspect first
#unlink or warn "Can't unlink $_: $!" for #files_to_del;
where that * in glob might as well have some pre-selection, if suitable. In particular, if the = is a literal character (and not an indicator printed by the shell, see footnote)‡ then glob "=*" will fetch files starting with it, and then you can pass those through a grep filter.
I exclude directories, identified by -d filetest, since we are looking for files (and to not mix with some scary language about directories from unlink, thanks to brian d foy comment).
If you'd need to scan subdirectories and do the same with them, perhaps recursively -- what doesn't seem to be the case here? -- then we could employ this logic in File::Find::find (or File::Find::Rule, or yet others).
Or read the directory any other way (opendir+readdir, libraries like Path::Tiny), and filter.
† Or, a quick one-liner ... print (to inspect) what's about to get blown away
perl -wE'say for grep { /^\W[0-9]+\.[0-9]+/ and not -d } glob "*"'
and then delete 'em
perl -wE'unlink or warn "$_: $!" for grep /^\W[0-9]+\.[0-9]+/ && !-d, glob "*"'
(I switched to a more compact syntax just so. Not necessary)
If you'd like to be able to pass a directory to it (optionally, or work in the current one) then do
perl -wE'$d = shift//q(.); ...' dirpath (relative path fine. optional)
and then use glob "$d/*" in the code. This works the same way as in the script above -- shift pulls the first element from #ARGV, if anything was passed to the script on the command line, or if #ARGV is empty it returns undef and then // (defined-or) operator picks up the string q(.).
‡ That leading = may be an "indicator" of a file type if ls has been aliased with ls -F, what can be checked by running ls with suppressed aliases, one way being \ls (or check alias ls).
If that is so, the = stands for it being a socket, what in Perl can be tested for by the -S filetest.
Then that \W in the proposed regex may need to be changed to \W? to allow for no non-word characters preceding a digit, along with a test for a socket. Like
my $re = qr/^\W? [0-9]+ \. [0-9]+/x;
my #files_to_del = grep { /$re/ and -S } glob "$dir/*";

Answer 2

Why not just:
$ rm =*
Sometimes, shell commands are the best option.

Answer 3

In these cases, I use perl to merely filter the list of files:
ls | perl -ne 'print if /\A\W\d+\.\d+/a' | xargs rm
And, when I do that, I feel guilty for not doing something simpler with an extended pattern in grep:
ls | grep -E '^\W\d+\.\d+' | xargs rm
Eventually I'll run into a problem where there's a directory so I need to be more careful about the file list:
find . -type f -maxdepth 1 | grep -E '^\./\W\d+\.\d+' | xargs rm
Or I need to allow rm to remove directories too should I want that:
ls | grep -E '^\W\d+\.\d+' | xargs rm -r

Answer 4

Here you go.
unlink( grep { /\W\d+\.\d+/ && !-d } glob( "*" ) );
This matches the filename, and excludes directories.

Answer 5

To delete filenames matching this: /\W\d+\.\d+/ pcre, use the following one-liners...
1> $fn is a filename... I'm also removing the my keywords since the one-liner doesn't have to worry about perl lexical scopes:
perl -e 'foreach $fn (grep { /\W\d+\.\d+/ } glob "*") {$cmd1="rm $fn";`$cmd1`;}'
2> Or as Andy Lester responded, perhaps his answer is as efficient as we can make it...
perl -e 'unlink(grep { /\W\d+\.\d+/ } glob "*");'