How to alter AWK source/input file

[Guest_imported]

The man page for awk clearly states that awk can be used to alter the contents of the source/input file. But how is this done??? It implies that it does not mean you need to pipe/re-direct the output to the input file.

Thanks.

 

[fcail]

Hi,

During the execution of an END action, the variable FILENAME contain the name of the last input file processed.
You can use it to modify the file like this :
awk 'END{ print "END OF FILE" > FILENAME}' file

Regards.

Fcail

 

[marsd]

.
I didn't get that from the man page.
Like any system command if you want the output saved you
can write to file or to memory.

op=$(awk ' {
if ($0 ~ /bogusstring/) {
printf "%s", substr(1,1,$0)
}' targetfile) ; test -z "$op" && echo "Nochar."

or redirect to file in or out of the awk program:

awk ' /[A-Z]/ {
print $0
}' targetfile > holdfile
-----------------------------
awk ' /[0-9]\{2,4\}/ {
printf "%d", $0 >> "/home/me/badnumpats"
}' target

Bye.