Need help on grep command

wjs1990 · 12-14-2009, 09:27 PM

Hi all,
For example, i have two similar line "net.ipv4.tcp_syncookies = 1" and "net.ipv4.tcp_syncookies =1". The difference is just that one of them have space between the "=" and "1", and the other one does not have.
Then i used, the command " grep -v "^#" /etc/sysctl.conf | grep -w net.ipv4.tcp_syncookies | awk -F= '{print $2}' ". The results i get will be " 1" and "1" for the two lines respectively.
So, does anyone have any idea on how can i get the result "1" for both lines, using the same command.

Thanks

ghostdog74 · 12-14-2009, 09:35 PM

just one awk command will do

Code:

awk -F'= ' '!/^#/&&/net.*ipv4.*tcp_syncookies/{print $2}' /etc/sysctl.conf

or using the shell

Code:

while read -r line
do
    case "$line" in
       net.ipv4.tcp_syncookies*)
       IFS="="
       set -- $line
       echo ${2// }
    esac
done <"/etc/sysctl.conf"

syg00 · 12-14-2009, 09:59 PM

Code:

sed -nr 's:(net.ipv[^=]*=)(.*):\2:p' /etc/sysctl.conf