Date: Tue, 12 May 1998 11:50:00 -0700 (PDT) From: Tor Egge <Tor.Egge@idi.ntnu.no> To: freebsd-bugs@FreeBSD.ORG Subject: Re: bin/6557: /bin/sh && IFS Message-ID: <199805121850.LAA26222@freefall.freebsd.org>
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The following reply was made to PR bin/6557; it has been noted by GNATS.
From: Tor Egge <Tor.Egge@idi.ntnu.no>
To: dima@best.net
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: bin/6557: /bin/sh && IFS
Date: Tue, 12 May 1998 20:46:16 +0200
> Try to run this script:
>
> #!/bin/sh
> XXX=/1:/2:/3:
> IFS=:
> echo /0:$XXX
>
> The expected result should be: "/0 /1 /2 /3"
> However, with current /bin/sh it's: "/0:/1 /2 /3"
According to "X/Open Commands and Utilities Issue 4, Version 2"
Section 2.6 "Word Expansion", field splitting is performed on the
portions of the fields generated by tilde expansion, parameter
expansion, command substitution and arithmetic expansion.
i.e. your
echo /0:$XXX
should give
Before Word Expansion: /0:$XXX
after tilde expansion,
parameter expansiion,
command substitition and
arithmetic expansion: /0:/1:/2:/3:
^^^^^^^^^
This is the portion of the field
being the result of expansion. Any
field splitting should only be
performed on this portion.
after field splitting: /0:/1 /2 /3
after pathname expansion: /0:/1 /2 /3
after quote removal: /0:/1 /2 /3
Correct field splitting results in 4 fields.
`/0:/1'
`/2'
`3'
`'
The last (empty) field should not be removed, since it is not the complete
expansion appropriate for a word (the word being `/0:$XXX' (without quotes)).
ksh93 gives almost the same result as our /bin/sh (for this example).
Unfortunately, it incorrectly removes the last field.
bash incorrectly performs field splitting on portions of the fields that
are not the result of expansion or substitution.
bash also incorrectly removes the last field.
- Tor Egge
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