On 13Jun2007 18:18, Michael Sullivan <[EMAIL PROTECTED]> wrote:
| Is there a Linux utility that will return the position of the first
| occurrence of a specific character? Ex:
|
| echo "example" | char-utility 'x' would return 2?
A tiny python or awk or perl script?
There isn't a utility specially made for that particular operation that
I know of. On some systems this:
echo example | { IFS=x; read a b; expr length "$a"; }
Gets you "1". It is not portable (expr does not have a "length" operator
on all systems). However, it is a bit of a step to get the 2, because
you can't just add 1 - you do not know if there was an "x". (Going
"echo a | ..." also gets "1". This:
sep=x # in your hypothetical script you would say "sep=$1"
echo example \
| { read -r line
case $line in
*$sep*)
# pick a marker that is not the separator
if [ "x$sep" = x_ ]
then mark=:
else mark=_
fi
# rewrite $1 etc using $line, split up by $sep
IFS=$sep set -- $mark$line
expr length "$1"
;;
*)
echo 0
;;
esac
}
Should do the trick without resorting to awk/python/perl at all.
You would put the whole { ... } bit into a shell script, setting
$sep from $1.
The $mark serves two purposes: firstly it ensures that there is at least
one character in $1 (otherwise strings starting with the separator would
not come out right) and it also increases the length of $1 by one
character, which neatly gets you the position of the separator.
--
Cameron Simpson <[EMAIL PROTECTED]> DoD#743
http://www.cskk.ezoshosting.com/cs/
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