How do I compare file names in two directories in shell script?

Question

Right now, this is what my code looks like:

#!/bin/bash

Dir1=$1
Dir2=$2

for file1 in $Dir1/*; do
    for file2 in $Dir2/*; do
        if [[ $file1 == $file2 ]]         


        

Answer 1

Your comparison fails because Dir1/foo is not the same as Dir2/foo. Instead, if you change to one directory, your * will expand to just the filenames:

#!/bin/bash

Dir1="$1"
Dir2="$2"

if ! cd "$Dir1"; then
  echo "ERROR: Couldn't find directory $Dir1" >&2
  exit 1
fi

if [[ ! "$Dir2" =~ ^/ ]]; then
  echo "ERROR: Second directory must be a full path." >&2
  exit 1
fi

for file1 in *; do
    if [ -f "$Dir2/$file1" ]; then
        echo "$file1 is contained in both directories"
    fi
done

Note that this only matches file names. If you want to make sure it's really the same file, you should use cmp to compare them.