Golfing the Extraction of IP Addresses from ifconfig

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October 03, 2011, 09:53

:D

time ifconfig eth0 | awk  '/inet adr:/ { print substr($2,5,length($2)) }'
#real   0m0.009s
#user   0m0.001s
#sys    0m0.010s

time ifconfig eth0 | grep 'inet adr:' | cut -d: -f2 | awk '{ print $1}'
#real   0m0.014s
#user   0m0.003s
#sys    0m0.017s

time TOTO=$(ifconfig eth0); TOTO=${TOTO##*adr\:}; TOTO=${TOTO%% *}
#real   0m0.007s
#user   0m0.002s
#sys    0m0.004s

time ifconfig eth0 | sed '/inet\ /!d;s/.*r://g;s/\ .*//g'
#real   0m0.008s
#user   0m0.001s
#sys    0m0.009s

time ip addr show eth0 | grep -Po '\d+\.\d+\.\d+\.\d+\/\d+' | cut -d '/' -f 1
#real   0m0.009s
#user   0m0.002s
#sys    0m0.011s

time ip addr show eth0 | awk '/inet/ { print substr($2,0,length($2)-3) }'
#real   0m0.007s
#user   0m0.001s
#sys    0m0.009s

time TOTO=$(ip addr show eth0); TOTO=${TOTO##*inet}; TOTO=${TOTO%%/*}; echo $TOTO
#real   0m0.005s
#user   0m0.002s
#sys    0m0.004s

time ifconfig eth0|perl -nE'/dr:(\S+)/&&say$1'
#real   0m0.013s
#user   0m0.005s
#sys    0m0.012s

time ifconfig eth0|perl -nE'/dr:(\S+)/&&say$1'
#real   0m0.013s
#user   0m0.005s
#sys    0m0.012s

time ip addr show eth0|perl -nE'/inet (\S+)\// && say $1'
#real   0m0.013s
#user   0m0.005s
#sys    0m0.011s
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