How-To on Perl one-liners

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

Does anyone know of a good beginners tutorial on writing Perl one-liners? I constantly find myself looking at a problem that I know is trivial to solve, but I simply haven't written enough Perl (and no one-liners) to be able to take the problem from "theoretically trivial" to actually trivial.

For example, I have a directory of MS Worm (er, Word) files. I want to run them all through antiword to convert them to text. In English I'd say:

for each doc file, run antiword, redirecting output to a file with the same filename, but the txt extension.

And that's where I get stopped - I don't know enough about the syntax to turn my tiny problem into a tiny solution. So, any good tutorials around? There seems to be lots of reference to example programs, and lots of scripting tutorials, but not enough hand-holding for my sad self. Thanks.

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Re: How-To on Perl one-liners by tlm (Prior) on Apr 03, 2005 at 21:59 UTC
Did you look at cog's presentation (with ambs) and paper? the lowliest monk	[reply]
Re^2: How-To on Perl one-liners by cog (Parson) on Apr 03, 2005 at 22:07 UTC
Wow... I was just going to mention that, and you beat me to it... :-)	[reply]
Re^3: How-To on Perl one-liners by thekestrel (Friar) on Apr 04, 2005 at 00:58 UTC
Cog, Great presentation, a lot of things I didn't know. Thanks =). Regards Paul.	[reply]
Re: How-To on Perl one-liners by Thilosophy (Curate) on Apr 03, 2005 at 22:09 UTC
There is a nice tutorial on mass-editing of files on perl.com. The complete list of all the useful command line switches is in the perlrun manual. What I like to do is combine Perl (to process the files) with the UNIX command line tool "find" (to make the list of files to hand to Perl). If you are on Windows, you can still go with the File::Find module (examples for this are in above tutorial). Another thing to watch out for if you are writing one-liners with "perl -e" is that you easily run into quoting problems (totally depends on the shell you are using), see Escaping characters in one-liners.	[reply]
Re: How-To on Perl one-liners by petdance (Parson) on Apr 03, 2005 at 22:36 UTC
See also my Field Guide To Perl Command Line Switches xoxo, Andy	[reply]
Re: How-To on Perl one-liners by ikegami (Patriarch) on Apr 03, 2005 at 22:13 UTC
Perl's not needed here. From prompt: `for %q in (.doc) do antiword "%q" > "%~nq.txt"` From batch file: `for %%q in (.doc) do antiword "%%q" > "%%~nq.txt"`	[reply] [d/l] [select]
Re^2: How-To on Perl one-liners by willyyam (Priest) on Apr 04, 2005 at 03:42 UTC
Absolutely true, and thank you for the code. However, I work on several systems, all of which have Perl, but not all of which have a consistent or sane shell. I believe the relevant quote is, "It is easier to port a shell than a shell script." My thinking in asking the question is, if I grok Perl one-liners, I don't need shell scripting nearly as much.	[reply]
Re^3: How-To on Perl one-liners by Mugatu (Monk) on Apr 04, 2005 at 16:54 UTC
if I grok Perl one-liners, I don't need shell scripting nearly as much Indeed, but with oneliners, you still need to know the shell fairly well. I'm not implying you don't, but I'm just trying to make the point. There are many shell gotchas involved when writing oneliners. Most common are quoting and glob expansion (or expansion in general) woes. Also, it's often more natural to use a perl oneliner as part of the pipeline, rather than the entire thing. This requires knowing the shells you're working with. There's really no [reasonably convenient] way of avoiding it. :-)	[reply]
Re: How-To on Perl one-liners by ww (Archbishop) on Apr 03, 2005 at 22:07 UTC
by inference, the big issue for you is apt to be correctly escaping DOS shell characters such as \, on which answers can be found at MS or perhaps even with a supersearch here. Re the rest, you can turn a script-file into a one liner for most tasks on the order of what you pseudo-coded by simply removing the returns. Now, yes, that's a tad oversimplified, but as a mechanism for learning what you ask about, those that don't work are probably as instructive as those that do (ww is the monk formerly known as schodckwm)	[reply]
Re^2: How-To on Perl one-liners by willyyam (Priest) on Apr 04, 2005 at 03:33 UTC
I appreciate the advice. It reminds me that I need to be explicit about what platform I'm using. Too much time talking only to people who use one OS limits my thinking. I use Linux, but it is plainly very good to know about shell escapes. Thanks again.	[reply]
Re: How-To on Perl one-liners by brian_d_foy (Abbot) on Apr 04, 2005 at 01:20 UTC
There are many great resources that people have already mentioned, but as an old-timer, I fondly remember Randal's first Unix Review column. :) -- brian d foy <brian@stonehenge.com>	[reply]
Re: How-To on Perl one-liners by davido (Cardinal) on Apr 04, 2005 at 04:46 UTC
For Yet Another Perl One-Liners introduction, have a look at this one (shameless plug, I'm the author): Re: One Liners. Dave	[reply]
Re: How-To on Perl one-liners by mhearse (Chaplain) on Apr 04, 2005 at 02:52 UTC
There was a good article on this in last month's issue of SysAdmin magazine, also by merlyn.	[reply]
Re: How-To on Perl one-liners by strat (Canon) on Apr 04, 2005 at 07:33 UTC
On my homepage www.fabiani.net -> Vortraege -> "Perl in der Kommandozeile" there is a powerpoint presentation (afraid it is in german) of a talk I had some years ago Best regards, perl -e "s>>F>e=>y)\martinF)stronat)=>print,print v8.8.8.32.11.32"	[reply]
Re: How-To on Perl one-liners by chanio (Priest) on Apr 05, 2005 at 06:29 UTC
For oneliners, I am fond of Ben Okopnik's articles ! They are fun, and the guy knows a lot ! You should search at the complete collection of his articles. There are some lessons of perl that he faced as complete one-liners. For a time, I thought that perl could only do one-liners :) . .{\('v')/} C H E E R U P ! _`(___)' ___a_l_b_e_r_t_o_________ Wherever I lay my KNOPPIX disk, a new FREE LINUX nation could be established.	[reply]

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