Bash: Loop over files listed in a text file and move them

Question

I have a directory (directory A) with 10,000 files in it. I want to move some of them to directory B and the others to directory C. I made a text file that contains the names o

Answer 1

You have to use BASH? What about Perl or Kornshell? The problem here is that Bash doesn't have hash keyed arrays (Kornshell and Perl do). That means there's no simple way to track what files go where. Imagine in Perl:

my %directoryB;   #Hash that contains files to move to Directory B
my %directoryC;   #Hash that contains files to move to Directory C

open (TEXT_FILE_B, "textFileB") or die qq(Can't open "textFileB");
while (my $line = ) {
    chomp $line;
    $directoryB{$line} = 1;
}
close TEXT_FILE_B;

open (TEXT_FILE_C, "textFileC") or die qq(Can't open "textFileC");
while (my $line = ) {
    chomp $line;
    $directoryC{$line} = 1;
}
close TEXT_FILE_C;

The above lines create two hashes. One for files that need to be moved to Directory B and one for files that need to be moved to Directory C. Now, all I have to do is look at my hash and decide:

foreach my $file (@directory) { #A little cheating here...
   if (exists $directoryB{$file}) {
       move ($file, $directoryB);
   } elsif (exists $directoryC{$file}) {
       move ($file, $directoryC)
}

My if statements can now look to see if a key has been defined in that hash. If it has, I know the file can be moved into that directory. I only have to read the two text files once. After that, my two hashes will store which files move to one directory and which to the other.

---

However, we don't have hashes, so we'll use grep to see if the file name is in the directory. I'll assume that you have one file name on each line.

ls | while read file
do
   if grep -q "^${file}$" textFileB
   then
       mv $file $directoryB
   elif grep -q "^${file}$" textFileC
   then
       mv $file $directoryC
   fi
done

The grep -q will search your two text files to see if the matching file is there. If it is, it'll move the file to that directory. It's not very efficient since it has to search the entire text file each and every time. However, it's pretty efficient, and you're only talking about 10,000 files, so the whole operation should only take a few minutes.