mjhjmtu

I am writing a bash script and want it to tell me if the names of the files in a directory appear in a text file and if not, remove them.

Something like this:

counter = 1
numFiles = ls -1 TestDir/ | wc -l 
while [$counter -lt $numFiles]
do
 if [file in TestDir/ not in fileNames.txt]
 then
 rm file
 fi
 ((counter++))
done

So what I need help with is the if statement that is still pseudo code.

Rather than saving the file list in a variable, loop over the names:

for name in TestDir/*; do
 # the rest of the code
done

To test whether $name occurs in the fileNames.txt, use grep -q:

for name in TestDir/*; do
 if ! grep -qxF "$name" fileNames.txt; then
 echo rm "$name"
 fi
done

The -F makes grep perform a string comparison rather than a regular expression match. With -q we get no output from grep, just an exit status that we can use with the if statement (true if the string was found but the exclamation mark inverts the sense of the test). The -x tells grep that the string $name needs to match a whole line, from start to finish, not just a part of a line.

I have protected the actual rm with echo. Run and make sure that the correct files gets deleted.

If the filenames are listed without the TestDir path, then change $name in the grep command to $name##*/:

for name in TestDir/*; do
 if ! grep -qxF "$name##*/" fileNames.txt; then
 echo rm "$name"
 fi
done

This will look for the filename portion of the path in $name rather than the full path including TestDir.

With zsh:

expected=($(f)"$(<fileNames.txt)") || exit
cd TestDir || exit
actual=(*(D))
superfluous=($actual:)
if (($#superfluous)) 
 echo These files are not in the expected list:
 printf ' - %qn' $superfluous
 read -q '?Do you want to delete them? ' && rm -rf -- $superfluous

Here's a working version using your approach:

#!/bin/bash
fileList="$1"
targetDir="$2"

## Read the list of files into an associative array
declare -A filesInFile
while IFS= read -r file; do
 filesInFile["$file"]=1
done < "$fileList"

## Collect the files in the target dir
filesInDir=("$targetDir"/*);

for file in "$filesInDir[@]"; do
 file=$file##*/; # get the name of the file; remove path
 ## If this file has no entry in the array, delete
 if [[ -z "$filesInFile[$file]" ]]; then
 echo "rm $file"
 fi
done

Remove the echo to actually delete the files. Note that I am not checking if the number of files differs, since there didn't seem much point given that the number of files might be the same but you could still have files whose name isn't in the list.