Copy files on a list to another directory

Shell Programming and Scripting
1

Hi.

I have a list with file names like

testfile1.wav
testfile2.wav
testfile3.wav

and a folder that contains a large number of wav files (not only the ones on the list).

I would like to copy the files whose names are on the list from the wav file directory to a new directory.

I tried to write a Python script for this, but it doesn't work and I wondered if there's an easier option to do that.

Cheers,

Kat

2

If GNU cp is available (if you're on Linux for example) and if the filenames do not contain pathological characters (newlines or white spaces):

< list xargs cp -t target_dir --

If the filenames contain white spaces and you have GNU cp (this is will be much slower if the number of files is high):

< list xargs -I{} cp -t target_dir -- {}

This is similar, but noisy:

while IFS= read -r; do 
  cp -- "$REPLY" target_dir 
done < list

Another option, if the filenames do not contain embedded newlines
and the total length of their names is below the ARGS_MAX limit
of your system:

( IFS=$'\n'; cp -- $(<list) target_dir )

If your shell doesn't expand ansi strings $'...' , use a literal newline:

( 
  IFS='
' 
  cp -- $(<list) target_dir 
  )
1 Like
3

Thanks! I tried the first option but I received the error

cp: target `testfile.wav' is not a directory

I executed it like this:

cd'ed into the wav file directory and then:

< ../list.data xargs cp -- -t ./target_directory
4

Sorry, there was an error in the commands I posted. Try the new versions.
The double dash -- marks the end of options, so it should be after the -t option and its argument.

5

Hi,
I didnt understand what is difficult in this.. I have a suggestion.

for file in `cat list_file `                          /* list_file contains the wav files you want to copy
 do 
 cp source_dir/$file new_dir
 done
6

That is a useless use of cat and useless use of backticks, inherently dangerous because any file too long for a shell variable to hold will have some of its contents silently lost. It's also very inefficient. There's a much better way to do this, which doesn't attempt to store the entire file in memory at once, and uses pure shell built-ins:

while read LINE
do
        ...
done < filename
1 Like