Hi everyone, and welcome to another edition of IBOTD (IFS-bug-of-the-day),
featuring everyone's favorite Bourne shell kludge: word-splitting!
On today's episode - inconsistencies within assignments that depend upon
quoting. Though I can't take credit for discovering this -- it was pointed out
to me by some guys on IRC after demonstrating some other stuff.
And a quick test:
function expassign {
typeset -a a
a=("$@")
typeset var asn
while IFS= read -r asn; do
IFS=: command eval "$asn"
printf '%-14s... %s\n' "$asn" "$var"
done <<\EOF
var=${a[*]}
var="${a[*]}"
var=$*
var="$*"
var=${a[@]}
var="${a[@]}"
var=$@
var="$@"
EOF
}
${ZSH_VERSION+:} false && emulate ksh
expassign one:::two three:::four
Bash output: # I think...
var=${a[*]} ... one two three four # bad
var="${a[*]}" ... one:::two:three:::four # good
var=$* ... one:::two:three:::four # good
var="$*" ... one:::two:three:::four # good
var=${a[@]} ... one two three four # bad
var="${a[@]}" ... one:::two three:::four # good
var=$@ ... one two three four # bad
var="$@" ... one:::two three:::four # good
Zsh and pdkshes produce:
one:::two:three:::four
For all of the above, which I think is wrong for the last 4. ksh93 produces:
one:::two three:::four
for the last 4, which I think is correct.
--
Dan Douglas
