doc: document split's new --filter=CMD option

* doc/coreutils.texi (split invocation): Describe --filter=CMD.
* NEWS (New feature): Mention it.
This commit is contained in:
Jim Meyering 2011-04-30 09:52:20 +02:00
parent 2644e288e4
commit 09baf2287e
2 changed files with 31 additions and 2 deletions

10
NEWS
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@ -2,6 +2,16 @@ GNU coreutils NEWS -*- outline -*-
* Noteworthy changes in release ?.? (????-??-??) [?]
** New features
split accepts a new --filter=CMD option. With it, split filters output
through CMD. CMD may use the $FILE environment variable, which is set to
the nominal output file name for each invocation of CMD. For example, to
split a file into 3 approximately equal parts, which are then compressed:
split -n3 --filter='xz > $FILE.xz' big
Note the use of single quotes, not double quotes.
That creates files named xaa.xz, xab.xz and xac.xz.
* Noteworthy changes in release 8.12 (2011-04-26) [stable]

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@ -2992,8 +2992,8 @@ The program accepts the following options. Also see @ref{Common options}.
Put @var{lines} lines of @var{input} into each output file.
For compatibility @command{split} also supports an obsolete
option syntax @option{-@var{lines}}. New scripts should use @option{-l
@var{lines}} instead.
option syntax @option{-@var{lines}}. New scripts should use
@option{-l @var{lines}} instead.
@item -b @var{size}
@itemx --bytes=@var{size}
@ -3011,6 +3011,25 @@ possible without exceeding @var{size} bytes. Individual lines longer than
@var{size} bytes are broken into multiple files.
@var{size} has the same format as for the @option{--bytes} option.
@itemx --filter=@var{command}
@opindex --filter
With this option, rather than simply writing to each output file,
write through a pipe to the specified shell @var{command} for each output file.
@var{command} should use the $FILE environment variable, which is set
to a different output file name for each invocation of the command.
For example, imagine that you have a 1TiB compressed file
that, if uncompressed, would be too large to reside on disk,
yet you must split it into individually-compressed pieces
of a more manageable size.
To do that, you might run this command:
@example
xz -dc BIG.xz | split -b200G --filter='xz > $FILE.xz' - big-
@end example
Assuming a 10:1 compression ratio, that would create about fifty 20GiB files
with names @file{big-xaa.xz}, @file{big-xab.xz}, @file{big-xac.xz}, etc.
@item -n @var{chunks}
@itemx --number=@var{chunks}
@opindex -n