Bash script scenarios to handle file descriptor redirections correctly in a loop
I tried several approaches but none seem to work. I'm working with an scenario with file descriptor redirections in a loop within my bash script. The script is supposed to read from a log file, process each line, and redirect both standard output and behavior to separate files. However, I notice that the output file ends up empty, and I'm also getting a "bad file descriptor" behavior intermittently. Here's a simplified version of my code: ```bash #!/bin/bash exec 3>output.log exec 4>behavior.log while IFS= read -r line; do if [[ "$line" == *"behavior"* ]]; then echo "Processing behavior line: $line" >&4 else echo "Processing normal line: $line" >&3 fi done < my_log_file.log ``` I've verified that `my_log_file.log` exists and contains multiple lines, with some containing the word "behavior". However, after running the script, `output.log` remains empty, and `behavior.log` sometimes shows partial output or nothing at all. I've tried checking the file descriptors with `lsof` and ensuring that I have write permissions on both log files. Additionally, I added debugging statements to confirm that the loop is iterating correctly, and it seems to be working. I also tested redirecting directly to a file without using file descriptors, which works fine. What could be causing the file descriptor redirection to unexpected result in this context? Is there something I'm missing with how bash handles file descriptors in a loop? Any insight would be greatly appreciated! What are your experiences with this? What would be the recommended way to handle this?