Re^4: How to write a program to read stdin or command line?

Assuming I was talking about the general case, how is -p less flexible? And how does -l matter?

perl -nle "print bar($_) unless foo($_)"
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perl -ple "next if foo($_); $_=bar($_)"
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Comment on Re^4: How to write a program to read stdin or command line? Select or Download Code

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Re^5: How to write a program to read stdin or command line? by BrowserUk (Patriarch) on Oct 03, 2007 at 11:00 UTC
With `-p`, whilst you can conditionally undef `$_` to avoid it being printed; if you are also using `-l`, you will get unwanted blank lines: `C:\test>type junk.txt 1 2 3 4 5 C:\test>perl -nle"$_ & 1 and print" junk.txt 1 3 5 C:\test>perl -ple"$_ & 1 or undef $_ and next" junk.txt 1 3 5` [download] And in fact the next in your example serves no purpose: `C:\test>perl -ple"$_ & 1 or undef $_" junk.txt 1 3 5` [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]
Re^6: How to write a program to read stdin or command line? by ikegami (Patriarch) on Oct 03, 2007 at 13:36 UTC
Yeah, I was confused, sorry.	[reply]
Re^5: How to write a program to read stdin or command line? (-p next) by tye (Sage) on Oct 03, 2007 at 05:47 UTC
`perl -ple "next"` still prints every line, so, yes, `-p` is less flexible based on your fine examples. If you want to omit some lines from the output, you can't do that if you are also using `-l` My first reaction to that is that the final `-l` was supposed to be a `-p`. That would certainly make sense to me, but I can't say for sure that it is what was intended. - tye	[reply] [d/l] [select]


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