Grep a file which has spaces on it by expanding a variable

Question

I have a find result saved in a variable and I am protecting the spaces in filenames by adding a single quotes around the output. So the for loop works flawlessly.

My problem is when I intend to grep one of those files, it says "File does not exist" because is literally taking the single quotes as part of the filename.

How can I overcome this??

all_files=$(find . -type f -printf "'%p'")

for file in $all_files
do
       grep 'hello' $file ### this says "file.not found because of the single quotes
done

Answer 1

You're not protecting the value of the filenames by adding quotes to it in the output of find. The loop would still see 'a filename' as two things to iterate over. The quotes would also be part of the string, as you noticed.

Instead, run your grep from find:

find . -type f -exec grep 'hello' {} \;

This would execute grep once for each file found.

find . -type f -exec grep 'hello' {} +

This would execute grep for as many files as possible at once (and thus also output the file names for batches with more than one file, use the -h option with GNU grep or compatible to not print the file name).

Still with GNU grep:

grep -D skip -r 'hello' .

This would run grep recursively on the current directory, skipping non-regular files (like -type f does for find), but would still look into symlinks to regular files (as if using GNU find -xtype f).

Answer 2

Print all the file names having the pattern 'hello',

find . -type f -print0 | xargs -0 -L1 grep -l 'hello'

OR with a find with grep inline

find . -type f -exec grep -l 'hello' {} \;

OR more simply (in case you have only regular files)

grep -Rl 'hello' .

Answer 3

If you want to store the file list to later loop over it, best would be to store it in an array.

With bash:

readarray -td '' all_files < <(find . -type f -print0)
for file in "${all_files[@]}"; do
  grep hello "$file"
done

With zsh (same thing but get a sorted list as a bonus):

all_files=(./**/*(ND.))
for file ($all_files) grep hello $file

Answer 4

For anyone interested in how I solved this, I ended up with :

all_files=$( find . -type f -name *.txt -printf '%p' )

while read file
do
        grep 'hello' "$filename"
        .....
done <<< "$all_files"

I know it's a bad practice. But for my specific use case I needed to do a lot of things over each filename. Not just grepping. And it worked flawlessly now.

Thanks!