Grep filenames and use in select menu

Question

I am frequently copy-pasting files from a Windows share to a local folder. For this, I would like to have a small bash script where I can search for a file name, have a menu based on this search to select from and then finally copy the selected file to my local folder. As searching the local share every time again would cost me a lot of time (and the files don't change frequently), I have a list of all files in filelist.txt.

Through copy-pasting from the many help sites on the select menu I came up with the following code. However, there is a problem with the grep output and the select menu. Somehow, newline is not recognized by this and as an option #1 I have a list of all filenames and option #2 is quit. That means, the script doesn't split the grep output into different options...

How can I avoid this behaviour? What am I doing wrong? Can I use grep in this way or do I need to use a different function?

Script example_script:

#!/bin/bash
read -p 'What are you searching for?  ' file_search_name
prompt="Please select a file:"
options=$(grep $file_search_name $HOME/Local/Folder/filelist.txt)

PS3="$prompt "
select opt in "${options[@]}" "Quit" ; do 
  if (( REPLY == 1 + ${#options[@]} )) ; then
    exit

  elif (( REPLY > 0 && REPLY <= ${#options[@]} )) ; then
    echo  "You picked $opt which is file $REPLY"
    break

  else
    echo "Invalid option. Try another one."
  fi
done

cp ~/Windows/Share/"$opt" $HOME/Local/Folder/"$opt"

sample output:

$ example_script
What are you searching for?  File
1) File1.txt
File2.txt
File3.txt
...
2) Quit
Please select a file:

Answer 1

You need to store the results of grep as an array, not a string:

options=( $(grep $file_search_name $HOME/Local/Folder/filelist.txt) )

But that won't work well if your file names have spaces. So, use the mapfile builtin instead (see help mapfile for details), and you should also quote your variables. Here's a working version of your script:

#!/bin/bash
read -p 'What are you searching for?  ' file_search_name
prompt="Please select a file:"
mapfile -t options < <(grep "$file_search_name" "$HOME/Local/Folder/filelist.txt") 

PS3="$prompt "
select opt in "${options[@]}" "Quit" ; do 
  if (( REPLY == 1 + "${#options[@]}" )) ; then
    exit

  elif (( REPLY > 0 && REPLY <= "${#options[@]}" )) ; then
    echo  "You picked $opt which is file $REPLY"
    break

  else
    echo "Invalid option. Try another one."
  fi
done

To understand what is happening, try the following example:

$ cat file
foo
bar
baz
a line with spaces

Say you now grep for a:

$ grep a file
bar
baz
a line with spaces

If you save that as you would in your original script:

options=$( grep a file)

This is a single string. So, ${options[@]} expands to that single string:

$ for i in "${options[@]}"; do echo "Option: $i"; done
Option: bar
baz
a line with spaces

Now, try again but save as an array instead:

$ options=( $( grep a file) )
$ for i in "${options[@]}"; do echo "Option: $i"; done
Option: bar
Option: baz
Option: a
Option: line
Option: with
Option: spaces

That's better, at least it's an array, not a string, but as you can see it didn't handle the spaces well. This is where mapfile comes in:

$ mapfile -t options < <(grep "$file_search_name" "$HOME/Local/Folder/filelist.txt")
$ for i in "${options[@]}"; do echo "Option: $i"; done
Option: bar
Option: baz
Option: a line with spaces

The -t tells mapfile not to include the trailing newline character (\n) of each input line in the value read into the array.