bash execute multi command built with strings from pipe-CodePudding

We have ip rules

# ip rule ls
0:      from all lookup local
100:    from 10.10.0.114 lookup RT0
100:    from 10.8.0.118 lookup RT0
100:    from 10.10.0.97 lookup RT1
220:    from all lookup 220
32766:  from all lookup main
32767:  from all lookup default

and we want to execute the following command according to the ip rule ls result:

ip rule del from 10.10.0.114 lookup RT0
ip rule del from 10.8.0.118 lookup RT0
ip rule del from 10.10.0.97 lookup RT1

I have tried following command but got no luck

for i in $(ip rule ls | grep lookup | grep -v all | awk '{print $2,$3,$4,$5}'); do ip rule del $i;done

But it seems that was wrong

How can we do that?

CodePudding user response：

Try:

ip rule ls | awk '/lookup/ && !/all/{print "ip rule del", $2, $3, $4, $5;}' | sh

CodePudding user response：

You could try

#!/bin/bash
IFS='
'
for i in $(ip rule ls | grep lookup | grep -v all | awk '{print $2,$3,$4,$5}')
do
    echo $i | xargs ip rule del
done

CodePudding user response：

Try this Shellcheck-clean pure Bash (except for the ip) solution:

#! /bin/bash -p

ip rule ls  |   while read -r -a f; do
                    (( ${#f[*]} == 5 ))     || continue
                    [[ ${f[1]} == from ]]   || continue
                    [[ ${f[2]} != all ]]    || continue
                    [[ ${f[3]} == lookup ]] || continue
                    ip rule del from "${f[2]}" lookup "${f[4]}"
                done

It's hyper-picky about checking that the output from ip rule ls has exactly the expected format because I've found that it pays to be very careful when writing code that deletes things.