Bash script scenarios to capture output of a command with multiple pipes due to subshell behavior
I've encountered a strange issue with I've been banging my head against this for hours. I'm working with an scenario with a Bash script where I'm trying to capture the output of a command that uses multiple pipes. The command works perfectly fine when run directly in the terminal, but when I try to capture the output in a variable within a script, it returns nothing. Here's the command I'm using: ```bash result=$(cat somefile.txt | grep 'pattern' | sort -u | wc -l) echo "Number of unique matches: $result" ``` When I run this script, I expect to see the count of unique matches printed, but it outputs `Number of unique matches: ` with nothing after it. I've tried breaking down the command and running each part separately, and they all return expected results. Also, I've confirmed that `somefile.txt` contains matches for the pattern. I've also attempted to use `tee` to debug the pipeline, like this: ```bash cat somefile.txt | grep 'pattern' | sort -u | tee debug_output.txt | wc -l ``` This works and `debug_output.txt` contains the unique matches, but the output capturing still fails. I suspect this might be related to how Bash handles subshells or command substitutions. I am using Bash version 5.1.8(1)-release and running this on Ubuntu 20.04. Any insights on why the variable `result` is not capturing the output as expected? What could I be missing? Any help would be greatly appreciated! My development environment is Linux. I've been using Bash for about a year now. I'm open to any suggestions.