awk delimeter

[ogniemi]

how to explain that awk in red doesn't return version numbers?
is it caused by ++- in the variable?
is it possible to get it working with the variable?

$ A="libstdc++-devel"
$ rpm -qa|grep ^${A}-[0-9]
libstdc++-devel-3.3.2-5
[red]$ rpm -qa|grep ^${A}-[0-9]|awk -F "${A}" '{print $2}'|cut -d- -f2-[/red]

$ A="zlib"
[green]$ rpm -qa|grep ^${A}-[0-9]|awk -F "${A}" '{print $2}'|cut -d- -f2-[/green]
1.2.5-1
$

 

[feherke]

Hi

The [tt]FS[/tt] ( field separator ) is a regular expression and [tt]+[/tt] is quantifier ( meaning previous entity 1 or more times ) in regular expressions.

You have to escape it : [tt]awk -F "libstdc\\\\+\\\\+-devel" '{print $2}'[/tt]

Or using variable A : [tt]awk -F "${A//+/\\\\+}" '{print $2}'[/tt]

Tested in Bash and MKsh. ( In Bash 3 backslashes ( \ ) are enough, 4 works in both. )

Feherke.
[link feherke.github.com/]

http://feherke.github.com/

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