mjhjmtu

I am running my program on Unix computer.
It has 300 loop.
At each loop, it will generate 4 files, which call 1.txt, 2.txt, 3.txt, 4.txt.
And in the next loop, the new files will overwrite the old ones.
Now I want these files at the exactly loop1, loop 50, loop 100, and so on.
But I could not seat all day to wait and see the running program.
Is there any script can do a work as when these .txt files appear in running directory, rename it as a loop counter (first loop's 1.txt file will be 1_1.txt, second loop's 1.txt file will be 2_1.txt and so on...)

There are a couple of ways to do this. Which is most efficient will depend on how your script works. If you can edit your question to contain your script or a snippet at least, I'll edit this to reflect a more accurate answer for your situation.

Here's an example for loop that runs 300 times:

for i in 1..300; do
 echo "test$i" > 1.txt
 echo "test$i" > 2.txt
 echo "test$i" > 3.txt
 echo "test$i" > 4.txt
done

That, as it stands, will overwrite 1-4.txt each loop as you mention your script does.

here's a simple solution:

count=1
for i in 1..300; do
 echo "test$i" > $count_1.txt
 echo "test$i" > $count_2.txt
 echo "test$i" > $count_3.txt
 echo "test$i" > $count_4.txt
 ((count++))
done

This will mean that you will have files named 1_1.txt, to 300_1.txt