Re: xargs PF or BPF
Matthias Kilian wrote:
And watch out for silly file names containing whitespace.
BTW: if this is a contest on creative use of find(1) and other
standard tools:
$ find . -type f | sed '[EMAIL PROTECTED]@grep -l -- foo @' | sh
Yes, this isn't robust against whitespace, either PLUS it's
inefficient. But in some cases the find ... | sed ... | sh pattern
is quite useful.
Sometime ago I have had the same problem with spaces in filenames and
dealing with them as xargs parameters. There I have used (here only as
an example):
find . -print | grep -i ' ' | xargs -I {} ls -ald {}
FYI, that has been on a non-OpenBSD system.
I4m not at my OpenBSD system at the moment, so I can4t check whether
OpenBSD xargs supports the shown options. Maybe someone may test it.
One may check this at a directory with space-containing filenames.
Without the -I {} and {} parts you get funny output.
Have a nice day
Michael
--
Michael Schmidt MIRRORS:
DJGPP ftp://ftp.fh-koblenz.de/pub/DJGPP/
Ghostscript ftp://ftp.fh-koblenz.de/pub/Ghostscript/
Re: xargs PF or BPF
On Tue, 14 Feb 2006, Michael Schmidt wrote:
Matthias Kilian wrote:
And watch out for silly file names containing whitespace.
BTW: if this is a contest on creative use of find(1) and other
standard tools:
$ find . -type f | sed '[EMAIL PROTECTED]@grep -l -- foo @' | sh
Yes, this isn't robust against whitespace, either PLUS it's
inefficient. But in some cases the find ... | sed ... | sh pattern
is quite useful.
Sometime ago I have had the same problem with spaces in filenames and dealing
with them as xargs parameters. There I have used (here only as an example):
find . -print | grep -i ' ' | xargs -I {} ls -ald {}
FYI, that has been on a non-OpenBSD system.
I4m not at my OpenBSD system at the moment, so I can4t check whether OpenBSD
xargs supports the shown options. Maybe someone may test it.
One may check this at a directory with space-containing filenames.
Without the -I {} and {} parts you get funny output.
Well, -print0 in find and xargs -0 are designed to deal with that.
Sadly these are not in POSIX (which is not documented correctly in the
xargs case).
-Otto
Re: xargs PF or BPF
On Tue, Feb 14, 2006 at 11:39:45AM +0100, Otto Moerbeek wrote:
On Tue, 14 Feb 2006, Michael Schmidt wrote:
Matthias Kilian wrote:
And watch out for silly file names containing whitespace.
BTW: if this is a contest on creative use of find(1) and other
standard tools:
$ find . -type f | sed '[EMAIL PROTECTED]@grep -l -- foo @' | sh
Yes, this isn't robust against whitespace, either PLUS it's
inefficient. But in some cases the find ... | sed ... | sh pattern
is quite useful.
Sometime ago I have had the same problem with spaces in filenames and
dealing
with them as xargs parameters. There I have used (here only as an example):
find . -print | grep -i ' ' | xargs -I {} ls -ald {}
FYI, that has been on a non-OpenBSD system.
I4m not at my OpenBSD system at the moment, so I can4t check whether OpenBSD
xargs supports the shown options. Maybe someone may test it.
One may check this at a directory with space-containing filenames.
Without the -I {} and {} parts you get funny output.
Well, -print0 in find and xargs -0 are designed to deal with that.
Sadly these are not in POSIX (which is not documented correctly in the
xargs case).
Does this diff fix it? (I also added a comma after the last -R.)
-Ray-
Index: xargs.1
===
RCS file: /cvs/src/usr.bin/xargs/xargs.1,v
retrieving revision 1.15
diff -u -r1.15 xargs.1
--- xargs.1 12 Sep 2005 09:44:59 - 1.15
+++ xargs.1 14 Feb 2006 13:37:48 -
@@ -316,7 +316,8 @@
.St -p1003.2
compliant.
The
-.Fl J , o , P , R
+.Fl 0 , J , o , P ,
+.Fl R ,
and
.Fl r
options are non-standard
Re: xargs PF or BPF
On Tue, 14 Feb 2006, Ray Lai wrote:
On Tue, Feb 14, 2006 at 11:39:45AM +0100, Otto Moerbeek wrote:
On Tue, 14 Feb 2006, Michael Schmidt wrote:
Matthias Kilian wrote:
And watch out for silly file names containing whitespace.
BTW: if this is a contest on creative use of find(1) and other
standard tools:
$ find . -type f | sed '[EMAIL PROTECTED]@grep -l -- foo @' | sh
Yes, this isn't robust against whitespace, either PLUS it's
inefficient. But in some cases the find ... | sed ... | sh pattern
is quite useful.
Sometime ago I have had the same problem with spaces in filenames and
dealing
with them as xargs parameters. There I have used (here only as an
example):
find . -print | grep -i ' ' | xargs -I {} ls -ald {}
FYI, that has been on a non-OpenBSD system.
I4m not at my OpenBSD system at the moment, so I can4t check whether
OpenBSD
xargs supports the shown options. Maybe someone may test it.
One may check this at a directory with space-containing filenames.
Without the -I {} and {} parts you get funny output.
Well, -print0 in find and xargs -0 are designed to deal with that.
Sadly these are not in POSIX (which is not documented correctly in the
xargs case).
Does this diff fix it? (I also added a comma after the last -R.)
I already committed a similar diff,
-Otto
-Ray-
Index: xargs.1
===
RCS file: /cvs/src/usr.bin/xargs/xargs.1,v
retrieving revision 1.15
diff -u -r1.15 xargs.1
--- xargs.1 12 Sep 2005 09:44:59 - 1.15
+++ xargs.1 14 Feb 2006 13:37:48 -
@@ -316,7 +316,8 @@
.St -p1003.2
compliant.
The
-.Fl J , o , P , R
+.Fl 0 , J , o , P ,
+.Fl R ,
and
.Fl r
options are non-standard
Re: xargs PF or BPF
On Monday 13 February 2006 17:13, Stuart Henderson wrote:
On 2006/02/13 16:53, Jason Crawford wrote:
On 2/13/06, Matthias Kilian [EMAIL PROTECTED] wrote:
On Mon, Feb 13, 2006 at 02:03:27PM -0700, Diana Eichert wrote:
find /usr/src -name *.[c|h] -exec grep 'bpf.h' /dev/null {} \;
it's in quotes, this is handled by find, not the shell.
(b) pipeing to xargs(1) may be faster.
why?
As done by find -exec, correct?
grep foo 1 2 3 4 5 6 7 ...
vs.
As done by xargs?
grep foo 1
grep foo 2
grep foo 3
...
Wouldn't for a small list -exec be faster as it is a single invocation of the
grep vs multiple invocations of grep for xargs.
IIRC, the reason xargs exists is to get around limits posed by the number of
args an application like rm or grep can take when passed a large list of
arguments like, say, a recursive find for old files in your spam
quarantine :-).
Tim Donahue
Re: xargs PF or BPF
On 2006-02-13 18:10:53 -0500, Tim Donahue wrote: As done by xargs? grep foo 1 grep foo 2 grep foo 3 quote src=xargs(1) Any arguments specified on the command line are given to the utility upon each invocation, followed by some number of the arguments read from stan- dard input. The utility is repeatedly executed until standard input is exhausted. /quote Wouldn't for a small list -exec be faster as it is a single invocation of the grep vs multiple invocations of grep for xargs. There won't be more invocations than necessary. IIRC, the reason xargs exists is to get around limits posed by the number of args an application like rm or grep can take when passed a large list of arguments like, say, a recursive find for old files in your spam quarantine :-). That is _one_ reason. Best Martin -- http://www.tm.oneiros.de
Re: xargs PF or BPF
On Tue, 14 Feb 2006, noob lenoobie wrote: On Mon, 13 Feb 2006, Matthias Kilian wrote: (b) pipeing to xargs(1) may be faster. Why so many people is using xargs ? I mean for instance why bother use xargs AND a pipe to do somthing like this : find ./ -type f -print | xargs -i rm -f Instead of rm -f $(find ./ -type f -print) Because that will fail when there are too many arguments, and will probably break on filenames with spaces (use xargs -0 for these). -d
Re: xargs PF or BPF
On Feb 13, 2006, at 9:24 PM, Damien Miller wrote:
Because that will fail when there are too many arguments, and will
probably break on filenames with spaces (use xargs -0 for these).
Why not use -exec in find?
find . -type f -name ttt -exec rm {}\;
-- Pinski
Re: xargs PF or BPF
On 2/13/06, Damien Miller [EMAIL PROTECTED] wrote: Why so many people is using xargs ? I mean for instance why bother use xargs AND a pipe to do somthing like this : find ./ -type f -print | xargs -i rm -f Instead of rm -f $(find ./ -type f -print) Because that will fail when there are too many arguments, and will probably break on filenames with spaces (use xargs -0 for these). with either version, hilarity is sure to ensue when you discover an accidentally created -r file. always use --.
Re: xargs PF or BPF
On Feb 13, 2006, at 9:53 PM, Jason Crawford wrote:
On 2/13/06, Andrew Pinski [EMAIL PROTECTED] wrote:
On Feb 13, 2006, at 9:24 PM, Damien Miller wrote:
Because that will fail when there are too many arguments, and will
probably break on filenames with spaces (use xargs -0 for these).
Why not use -exec in find?
find . -type f -name ttt -exec rm {}\;
Because as stated many times on this list already (originally to
correct me), that will execute rm for each file, while piping to xargs
will only run rm once xargs stops getting input, or when it hits max
command line length, in which case it will execute another rm based on
input from the pipe.
Time to write your own program in C instead if the time to invoke
rm is taking too much time.
-- Pinski
Re: xargs PF or BPF
On 2/13/06, Andrew Pinski [EMAIL PROTECTED] wrote:
On Feb 13, 2006, at 9:24 PM, Damien Miller wrote:
Because that will fail when there are too many arguments, and will
probably break on filenames with spaces (use xargs -0 for these).
Why not use -exec in find?
find . -type f -name ttt -exec rm {}\;
Because as stated many times on this list already (originally to
correct me), that will execute rm for each file, while piping to xargs
will only run rm once xargs stops getting input, or when it hits max
command line length, in which case it will execute another rm based on
input from the pipe.
Jason
Re: xargs PF or BPF
On 2/13/06, Andrew Pinski [EMAIL PROTECTED] wrote:
On Feb 13, 2006, at 9:53 PM, Jason Crawford wrote:
On 2/13/06, Andrew Pinski [EMAIL PROTECTED] wrote:
On Feb 13, 2006, at 9:24 PM, Damien Miller wrote:
Because that will fail when there are too many arguments, and will
probably break on filenames with spaces (use xargs -0 for these).
Why not use -exec in find?
find . -type f -name ttt -exec rm {}\;
Because as stated many times on this list already (originally to
correct me), that will execute rm for each file, while piping to xargs
will only run rm once xargs stops getting input, or when it hits max
command line length, in which case it will execute another rm based on
input from the pipe.
Time to write your own program in C instead if the time to invoke
rm is taking too much time.
No point, xargs does what I need it to do, and is much more efficient
than having find execute rm itself. The fewer times you call execve(2)
the better.
Jason
Re: xargs PF or BPF
On Mon, 13 Feb 2006, Andrew Pinski wrote:
On Feb 13, 2006, at 9:24 PM, Damien Miller wrote:
Because that will fail when there are too many arguments, and will
probably break on filenames with spaces (use xargs -0 for these).
Why not use -exec in find?
find . -type f -name ttt -exec rm {}\;
this conversation is going in circles. Look back a couple of messages
in this very thread
Re: xargs PF or BPF
On Feb 13, 2006, at 10:00 PM, Jason Crawford wrote: Time to write your own program in C instead if the time to invoke rm is taking too much time. No point, xargs does what I need it to do, and is much more efficient than having find execute rm itself. The fewer times you call execve(2) the better. One execve is enough? Then rewriting the script into C will save all execve. Do you think rm(1) does anything special, other than remove(3)? -- Pinski
Re: xargs PF or BPF
On Mon, 13 Feb 2006, Andrew Pinski wrote: Time to write your own program in C instead if the time to invoke rm is taking too much time. rm *is* a small program written in C. You need to consider how the tools actually invoke it - think about it for a while. -d
Re: xargs PF or BPF
On Mon, Feb 13, 2006 at 06:32:53PM -0800, Ted Unangst wrote: find ./ -type f -print | xargs -i rm -f Instead of rm -f $(find ./ -type f -print) Because that will fail when there are too many arguments, and will probably break on filenames with spaces (use xargs -0 for these). with either version, hilarity is sure to ensue when you discover an accidentally created -r file. always use --. And watch out for silly file names containing whitespace. BTW: if this is a contest on creative use of find(1) and other standard tools: $ find . -type f | sed '[EMAIL PROTECTED]@grep -l -- foo @' | sh Yes, this isn't robust against whitespace, either PLUS it's inefficient. But in some cases the find ... | sed ... | sh pattern is quite useful. Ciao, Kili
