I have a directory with data files having longish, informative names; part of each file name is a unique numeric identifier (other parts are date_time, file type). I want to take a list of chosen numeric ID values, and look up the full path/file name that matches each item in the list.

So I use a file glob to match each ID value, but only half of the list elements come out as intended: 

$ ls test
bar_002.tst  baz_003.tst  faz_004.tst  foo_001.tst

$ cat test.list
001
002
003
004

$ perl -pale '$p=<test/*_$F[0].tst>; s/^/$p /' test.list
test/foo_001.tst 001
 002
test/baz_003.tst 003
 004

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I can't figure out why the glob only works on every other iteration, or how to make it work on every iteration. This perl 5.8.7, on both macosx and freebsd.

(The made-up example is simpler than the real case: the directory actually contains thousands of files, and I have a list of 200 ids to extract path/file strings for. I know there are other ways to do this, but I'm curious about the behavior of the file glob in this case.)

UPDATE: Nevermind -- I should have looked at perldoc -f glob first: 

 glob    In list context, returns a (possibly empty) list of filename
         expansions on the value of EXPR such as the standard Unix she
+ll
         /bin/csh would do. In scalar context, glob iterates through
         such filename expansions, returning undef when the list is
         exhausted.

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Just changing the one-liner to start with '($p)=...' did the trick. Sorry for the spurious post.

In reply to Problem with one-liner using file globs by graff

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