Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?

Re: Uncommon* but Useful Perl Command Line Options (for one-liners)

by ysth (Canon)
on Jan 29, 2004 at 01:51 UTC ( #324858=note: print w/replies, xml ) Need Help??

in reply to Uncommon* but Useful Perl Command Line Options for One-liners

so dealing with files originating from other OS needs the ability to change the value of \n
I would say "to change the value of $/". -0 certainly doesn't change \n.

There are also some funky details about how -0 works. First of all, -0[octal] is limited to 3 following octal digits. Anything beyond that is interpreted as a new bundled switch (e.g. -07770 is equivalent to -0777 -0 (which is equivalent to just -0)).

-0 with no following octal digits will set $/ to "\0", the null character. As you say, -00 does paragraph mode ($/ = "") instead. This applies to -000 and -0000 also; as above, -00000 etc is interpreted as two separate switches where the first is meaningless, creating the pleasant cycle:
-0\0 record separator
-00paragraph mode
-000paragraph mode
-0000paragraph mode
-00000\0 record separator
-000000paragraph mode
-0000000paragraph mode
-00000000paragraph mode
-000000000\0 record separator
-0000000000paragraph mode

Not just -0777, but any attempt to specify an octal character greater than 0377 (255 decimal), will trigger slurp mode.

And starting with 5.8.1, -0 will allow hex characters to be specified like -0x1ff (but you can't bundle it with other switches like -0x1ffw; for backward compatibility, that is interpreted as -0 -x1ffw instead of -0x1ff -w (see perlrun for details on the -x switch)). Any number of hexidecimal digits are permitted, but only the low 32-bits are used. This allows specifying any unicode character as the record separator. Paragraph mode or slurp mode cannot be specified with -0x; -0x0 sets $/ to "\0", not "", -0x1ff (the "equivalent" of -0777) sets $/ to "\x{1ff}", not undef.

-0x actually allows an extra "x" or "0x" after the first one (e.g. -0x0x0d or -0xx0); this can be construed as a bug.

  • Comment on Re: Uncommon* but Useful Perl Command Line Options (for one-liners)

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://324858]
[GrandFather]: That's ok when the signal is a voltage, but there are three axis accelerometers, gyroscopes and magnetometers in these things! A little invention is needed at times!
[Corion]: GrandFather: Yeah, in that aspect, hardware is far more a black box than software
[GrandFather]: Oh, and the manufacturer tells lies too! I'm sure they don't mean to, but I know for sure some of the stuff they say is just wrong. It's possible they don't understand what we are asking, but that's not a good look either
[Corion]: GrandFather: Ah, unit testing hardware is fun, especially when the hardware is uncalibrated ...
[GrandFather]: Us: "What scaling do we need to apply to the numbers from the SDK for the wibble?". Them: "Oh, the numbers from the SDK for the wibble are already correct, they don't need scaling"
[GrandFather]: In our code: wibble range 1 scale by 1, range 2 scale by 2, range 3 scale by 4, range 4 scale by 8

How do I use this? | Other CB clients
Other Users?
Others imbibing at the Monastery: (7)
As of 2017-08-24 07:16 GMT
Find Nodes?
    Voting Booth?
    Who is your favorite scientist and why?

    Results (365 votes). Check out past polls.