Bob Proulx wrote:
Chet Ramey wrote:
Toralf Förster wrote:
I'm wondering why in the example (see below) the right side is
prefixed with a '\' wheras the left side is unchanged.
...
[EMAIL PROTECTED] ~ $ echo "1 2 3 4" | while read a b c d; do [[ "$a" =
"$b" || "$a" = "$c" || "$a" = "$d" ]] && echo oops; done
+ read a b c d
+ echo '1 2 3 4'
+ [[ 1 = \2 ]]
+ [[ 1 = \3 ]]
+ [[ 1 = \4 ]]
Because the ==/!=/= operators are defined to match the rhs as a pattern
unless it's quoted. You quoted the original string, and the `set -x'
output is supposed to be re-usable as input, so the trace output is
quoted appropriately.
Of course that makes sense for the "==" and "!=" cases. But is that
true even for the "=" case? For the "=" case I thought it was
"STRING1 = STRING2" and not "STRING = PATTERN".
"When the == and != operators are used, the string to the right of the
operator is considered a pattern [...]"
From the description for [[ ]].
= and == should make have difference in behaviour.
J.
