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in Technique[技术] by (71.8m points)

bash - Printing a string value results not found

When I run my script, there is no output to the terminal.

This my code:

for ((h = 1 ; h < 4 ; h++ )); do 
    x=$(awk -v i=h -v j=17 'FNR == i {printf "%s ", $j}' newiptables.log)
        echo $x
done

This is the file

Dec 26 09:17:51 localhost kernel: IN=eth0 OUT= MAC=00:10:c6:a8:da:68:00:90:7f:9c:50:5a:08:00 SRC=198.252.206.16 DST=10.128.1.225 LEN=313 TOS=0x00 PREC=0x00 TTL=64 ID=59334 PROTO=TCP SPT=80 DPT=56506 WINDOW=46535 RES=0x00 ACK PSH URGP=0 
Dec 26 09:17:52 localhost kernel: IN=eth0 OUT= MAC=00:10:c6:a8:da:68:00:90:7f:9c:50:5a:08:00 SRC=198.252.206.16 DST=10.128.1.225 LEN=1440 TOS=0x00 PREC=0x00 TTL=64 ID=47303 PROTO=TCP SPT=80 DPT=56506 WINDOW=46535 RES=0x00 ACK URGP=0 
Dec 26 09:17:52 localhost kernel: IN=eth0 OUT= MAC=00:10:c6:a8:da:68:00:90:7f:9c:50:5a:08:00 SRC=198.252.206.16 DST=10.128.1.225 LEN=1440 TOS=0x00 PREC=0x00 TTL=64 ID=47559 PROTO=TCP SPT=80 DPT=56506 WINDOW=46535 RES=0x00 ACK URGP=0 
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by (71.8m points)

You are saying:

awk -v i=h -v j=17 ...

Note i=h which is equivalent to saying: i=0.

It seems that you wanted to say:

x=$(awk -v i=$h -v j=17 'FNR == i {printf "%s ", $j}' newiptables.log)
             ^
             |== refer to the variable h

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