Zsh Mailing List Archive
Messages sorted by: Reverse Date, Date, Thread, Author

Re: Splitting string to array removes pipe symbol

Vincent Stemen wrote:
> However, when the globsubst option is set, it removes the pipe '|'
> symbol when it does the split.  Here is the trace output.
>   +./t:62> cmd=uncompress foobar | cpio -i --quiet --unconditional
>   +./t:63> cmd=( uncompress foobar cpio -i --quiet --unconditional )

You have null_glob (or maybe csh_null_glob) set.  `|' is split to a
single bar.  Evaluation of the words takes place as if all the elements
of the array are arguments, which is different from evaluating as a
command.  (This is inevitable --- the only way of doing it differently
would be to parse the line again completely from scratch after the
glob_subst.)  In this case, the `|' is treated the same as (|),
i.e. either nothing or nothing, and removed since nothing matches it.
(You'd normally need the parentheses to stop it being evaluated as a
pipe, but it can't be in an argument list.)

You can fix this particular problem by quoting,
but only because that cancels the effect of glob_subst, so that `|' is
just an ordinary character.  This may not be what you want.  It's
likely to be very difficult to force the shell both to split a line into
words *and* to parse it again as a full command line without joining it
up again.

Most people would probably come up with something using `eval'.  What you
should do depends why you need to split it at all.

Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070

This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.

This footnote also confirms that this email message has been swept by
MIMEsweeper for the presence of computer viruses.


Messages sorted by: Reverse Date, Date, Thread, Author