subtractFiles.sh

#! /usr/bin/env bash

# Make sure the user gave the right arguments
# Might not include this in a script to be run automatically, since returning output different from expected might break things....
if [[ $# -eq 0 ]]; then
    echo
    echo "Example: subtractfiles.sh allFiles.csv filesToBeSubtracted.csv"
    echo
    exit 1 # Non zero exit code so the build system knows something went wrong and stops...
fi

AFILE=$1
UFILE=$2

for ALINE in $(cat $AFILE); do
    MATCH=0 # "Should" use a boolean for this, but it breaks things in the conditional...
    for ULINE in $(cat $UFILE); do
        
        # Determine if $ALINE is equivalent to $ULINE 
        if [ $ALINE = $ULINE ]; then
            MATCH=1
            break
        fi
    done
    if [[ $MATCH = 0 ]]; then
        echo $ALINE
    fi
done