如何在awk中使用循环

Question

I use the following command to extract 2nd column from table1.txt and get output as output1.txt

awk '{ print $2 }' table.txt > output.txt

How to use loop for five files ( table.txt , abc.txt , pqr.txt , skt.txt , mkt.txt ) to extract 2nd column in respective output files ( out_table.txt , out_abc.txt , out_pqr.txt , out_skt.txt , out_mkt.txt ) ?

Answer 1

you don't need to write a loop in awk. You could use the build-in variable FILENAME :

awk '{print $2 > "out_"FILENAME".txt"}' table.txt abc.txt pqr.txt skt.txt mkt.txt

Answer 2

使用FILENAME变量将相应的输出文件名用于输入一个：

awk '{ print $2 > "out_" FILENAME }' *.txt