How to use the awk variable $0

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Content of the script:

#! / bin/bash

For ip in `cat ip.lst`

Do

. / ssh.exp $ip > / dev/null 2 & > 1

Done

NK= `awk 'BEGIN {bs=4000000} / access/ {if ($1 > bs) {nk=NR-1;print nk}}' exp.log`

For nnk in $NK

Do

Awk-F "[@ |']" 'NR==' "$nnk"' {print $2} 'exp.log

Done

And then found the ghost of $0 in awk. So it was further simplified to this:

The code is as follows:

#! / bin/bash

For ip in

`cat ip.lst`

Do

. / ssh.exp $ip > / dev/null 2 & > 1

Done

Awk 'BEGIN {bs=4000000} / access/ {if ($1 > bs) print x}; {print $0}' exp.log | awk-F "[@ |']"'{print $2}'

I finally realized my dream of accomplishing it in one sentence. Yeah~ still doesn't quite understand this principle. Because print x _ 0 is the previous line, but print $0 is the line. Why? On the Internet, there is another way to write the line before printing, which makes it even more baffling:

Awk'/ regex/ {print (x = "?": X)}; {x = 0}'$1

After printing, the line looks like this:

Awk'/ regex/ {getline;print}'$1

But after all, this is just up and down, and if you want the first few lines, you still have to rely on NR.

Because of the streaming of awk, the x of print x has to wait until the next line to print.

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