Unix, Xenix and ODT General FAQ
Wildcard expansion (globbing) is performed by the shell. There
is a limit of 5120 bytes (5k) for the environment and command line
arguments put together, in all versions of SCO Xenix and SCO Unix
versions prior to OpenServer 5; more on OSR5 later. See also TA
This is particularly likely to be a problem under X, as it has a
habit of using a lot of environment space. It is also a problem
when running a command such as ls *.c in a directory
with a large number of files which match the filespec.
The general solution is to construct your command in such a way
that it does not have to include all of the filenames on the
command line. You can use the echo
command, which is built into the shells and therefore is not
subject to the 5k limit. For example, rather than rm
V*, you might try echo V* | xargs rm. A
similar, but somewhat more complex solution, might involve using
command to generate a list of filenames, and then using a command
such as grep
to filter them; ls | grep '^V' | xargs rm will perform
the same task as the above example.
You may also find the find
command to be useful in this; however, it works recursively so it
may not be appropriate in a directory with subdirectories. Please
consult the man pages for each of these commands to identify any
unexpected side effects they may cause.
Another alternative, in cases where the environment is
unnecessarily large, is to reduce its size. If you have some
environment variables that you never use (be careful with this, as
the system or some commands may use things you don't realize), you
can permanently remove them in your .profile (or
.login for C Shell users). You could also temporarily remove
some manually. To run a subshell without any of the environment
being passed to it, try running env - sh -c
On Linux, ARG_MAX is the maximum length of the buffer of arguments passedi, but a shell is not required to support that length. Also:
On a 32-bit Linux, this is ARGMAX/4-1 (32767). This becomes
relevant if the average length of arguments is smaller than
4. Since Linux 2.6.23, this function tests if the number
exceeds MAX_ARG_STRINGS in (2^32-1 =
4294967296-1). And as additional limit, one argument must
not be longer than MAX_ARG_STRLEN (131072).
And see ARG_MAX, maximum length of arguments for a new process.
OpenServer Release 5 makes two changes to cure this problem. The
default limit has been increased substantially (to 100k), which
should by itself fix almost all instances of "arglist too long". As
well, it is now a tunable kernel parameter, ( http://aplawrence.com/cgi-bin/ta.pl?arg=105076
MAXEXECARGS) so if the default isn't adequate, you can adjust it.
One exception: /bin/csh still has a hard-coded limit to the length
of a line. If you are using csh, you may wish to replace it with
tcsh (discussed below).
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