Cfrtjryk

It seems the -n option on the xargs found in SmartOS (and I assume Solaris) does not behave like any other version of xargs I've encountered.

Take this example:

Builtin /usr/bin/xargs (odd behavoir):

# printf 'onetwothree' | xargs -0 -I{} -n 1 echo "- {}"

- {} one

- {} two

- {} three

GNU Findutils /opt/local/bin/xargs (expected behavoir):

# printf 'onetwothree' | /opt/local/bin/xargs -0 -I{} -n 1 echo "- {}"

- one

- two

- three

Xargs from MacOS, NetBSD, and CentOS all behave the same as the last example. What's different about the SmartOS xargs?

From the SmartOS xargs manpage:

   -n number

                  Invokes utility using as many standard input arguments

                  as possible, up to number (a positive decimal integer)

                  arguments maximum. Fewer arguments are used if:



                      o      The command line length accumulated exceeds

                             the size specified by the -s option (or

                             {LINE_MAX} if there is no -s option), or



                      o      The last iteration has fewer than number, but

                             not zero, operands remaining.

From the Gnu Findutils xargs manpage:

   -n max-args, --max-args=max-args

          Use at most max-args arguments per command line.  Fewer than max-args arguments will be used if the size (see the -s option) is  exceeded,  un‐

          less the -x option is given, in which case xargs will exit.

I discovered this difference while porting a shell script and I'm curious if anyone knows why the behavoir is different.

You cannot combine the -I and -n options. That's what the standard says:

The -I, -L, and -n options are mutually-exclusive. Some
implementations use the last one specified if more than one is given
on a command line; other implementations treat combinations of the
options in different ways.

See also this and this.