Re^2: Does Perl 5 (or 6?) need another built-in variable for the -F switch?

You didn't try that, did you? It's not going to work. See, if $F is interpolated by the shell, you end up with:

    join(t, @F)
[download]

This is wrong on several accounts. First, inside the one-liner, you need to place quotes around $F, otherwise, at best you end up with bare words, but more likely, you end up with something that cannot be compiled (Try F=":") for instance. Second, the shell doesn't know "\t" as something special. It just sees an escaped t, and hence, F="\t" is equivalent to "t".

Also, the command line switches -line won't do what you expect it to do. It means "chomp of newlines, and add newlines to print, and modify the input file, leaving a backup with extension 'ne'".

You probably want (untested):

    F='  '  # Enter a tab here.
    perl -F"$F" -i -wlne "munge(@F); print join('$F',@F);" file
[download]

But you can to better, it can also work if you want to use single quotes for the one liner. The shell's quoting mechanism are superior to Perls in some expects. Exploit them:

   perl -F"$F" -i -wlpe 'munge(@F); $_ = join("'$F'",@F);'
[download]

Comment on Re^2: Does Perl 5 (or 6?) need another built-in variable for the -F switch? Select or Download Code

Replies are listed 'Best First'.
Re^3: Does Perl 5 (or 6?) need another built-in variable for the -F switch? by jbert (Priest) on Nov 03, 2006 at 10:01 UTC
I tried it with a : seperator, but you're right I didn't use the \t. Mea culpa.	[reply]
Re^4: Does Perl 5 (or 6?) need another built-in variable for the -F switch? by Anonymous Monk on Nov 03, 2006 at 11:47 UTC
Odd. Using \t does work (in the sense that it compiles) because `join(t, @F)` is valid Perl, and all it does is generate a warning. Using : however does not work, unless your Perl can compile `join(:, @F)`.	[reply] [d/l] [select]
Re^5: Does Perl 5 (or 6?) need another built-in variable for the -F switch? by jbert (Priest) on Nov 03, 2006 at 12:30 UTC
Hmmph. I (foolishly) re-typed for the comment (with an eye on the original) rather than cut-and-paste my test. You're absolutely right, this is what I'd used (from my .bash_history): `export F=: perl -na -F$F -e "shift @F; print join('$F', @F);" < foo` [download] This has the problems you noted if $F is anything special to the shell (e.g. \t, contains spaces, etc). Sorry for the lack of precision in quoting. No real excuses. Will try harder.	[reply] [d/l]