Greg Wooledge <wool...@eeg.ccf.org> writes:
> The 4.1 man page says:
>
> ${!prefix*}
> ${!pre...@}
> Names matching prefix. Expands to the names of variables whose
> names begin with prefix, separated by the first character of the
> IFS special variable. When @ is used and the expansion appears
> within double quotes, each variable name expands to a separate
> word.
>
> Actually, the IFS rule only applies when the "${!prefix*}" is quoted.
The IFS rules are the same as with $* and $...@.
> imadev:~$ IFS='+x'
> imadev:~$ echo ${!P*}
> P4CLIENT PAGER PATH PIPESTATUS PKG_CONFIG_PATH PPID PS1 PS2 PS4 PWD
${!P*} expands to P4CLIENT+PAGER+PATH+... and word splitting splits it
on any character in $IFS, which echo receives as separate arguments.
Try this to see the difference:
$ o=$IFS; IFS=+; a=${!P*}; IFS=$o; echo $a
> imadev:~$ echo "${!P*}"
> P4CLIENT+PAGER+PATH+PIPESTATUS+PKG_CONFIG_PATH+PPID+PS1+PS2+PS4+PWD
"${!P*}" expands to a single word, no word splitting is performed on it.
> I believe this is intended behavior (since it matches how $* works),
> and that the man page is simply misleading.
Parameter expansion and word splitting are two separate steps. The
quote above only talks about the former.
Andreas.
--
Andreas Schwab, sch...@linux-m68k.org
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"And now for something completely different."
