I don't want my ls command in my script to print results on screen

Question

I run "ls -lX" over files umbrella31_*.xvg. I run a command that searches the number on the fifth column of the ls command output, that is larger let's say than 20000. It looks like this:

ls -lX umbrella31_*log |  awk '{if($5 >=20000) {print}}' | wc -l

and outputs a number (the number of lines for which the number in column 5 is > 20000).

When I include the above command in a script:

#!/bin/bash -x


ls -lX umbrella31_*log |  awk '{if($5 >=20000) {print}}' | wc -l

and run it, I get in the screen the result of "ls" printed as well (which I don't want). How can I get my script behave like my on-screen command, and print only the desired number of lines?

Answer 1

Your script will print each of the commands in your pipeline to the terminal because you are running it with the -x flag. Fromman bash:

   -x        Print commands and their arguments as they are executed.

However, your approach using ls and wc is not the best way to count files.

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To find file that is >= 20000 you can use find:

find -type f -maxdepth 1 -name 'umbrella31_*log' -size +19999c -ls

(because of how find interpreters + sign (greater than rounded up) you get n+1, therefore the odd
-size n)

count output:
(when we count files we just print a newline because we dont really need an output)

wc -l < <(find -maxdepth 1 -type f -name 'umbrella31_*log' -size +19999c -printf \\n)

-maxdepth n
  Descend at most levels (a non-negative integer) levels of directories below the starting-points.
-size n
  File uses n units of space, rounding up.
-ls
  List current file in ls -dils format on standard output.

Answer 2

Updated Answer

After posting script used in the question it was discovered:

#!/bin/bash -x

was used where the -x option outputs all commands to the terminal.

Removing the -x solved the original problem.

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Original Answer

You're missing the argument flag indicator so this:

ls lX umbrella31_*log |  awk '{if($5 >=20000) {print}}' | wc -l

should be this instead:

ls -lX umbrella31_*log |  awk '{if($5 >=20000) {print}}' | wc -l

On my system looking for bash scripts it works like so:

$ ls -lX *.sh
-rwxrwxr-x 1 rick rick 4183 Jul  1 10:48 aptfileparse.sh
-rwxrwxr-x 1 rick rick  339 Jul 24 17:26 checkrunning.sh
-rwxrwxr-x 1 rick rick  506 Jul 15 17:54 Downloads.sh
-rwxrwxr-x 1 rick rick   78 Jul  6 11:28 runall.sh

$ ls -lX *.sh | awk '{if($5 >=200) {print}}' | wc -l
3