Replacing ' ' with '\ ' in bash

Question

I am trying to write a shell scripts that will back up every file in a directory. In oder to get the files I use

FILENAMES="$(find -maxdepth 1 -not -path './.*' -type f)"

which returns something containing all the names of the files.

If none of the filenames contain spaces then using

tar --exclude='archive.tar.bz2' -cvpjf archive.tar.bz2 $FILENAMES

does the job and all is fine.

However if there is a file names "bad filename.txt" the above approach does not work and tar will complain that it cannot find "bad" of "filename.txt".

I tried to fix this by using an inline replacement as described here, but that does not work:

TOARCHIVE=${FILENAMES// /'\ '}

Basically what this does is to replace the spaces in the appropriate position, IF I echo it. But tar does not seem to see the inserted '\'. If try the replacement code with two slashes, such as '\\' or '\\ ' tar will see both slashes and again complain.

Another solution to similar problems I saw was to make sure everything is in quotes, but that does not work for me since TOARCHIVE contains the names of multiple files.

You may want to use nul separator https://www.gnu.org/software/tar/manual/html_node/nul.html - and pass `-print0` to find. — ideasman42, Aug 07 '17 at 11:28

score 0 · Answer 1 · answered Aug 07 '17 at 11:38

0

For characters replacement, i suggest you to use sed, like this :

sed "s/\ /\\/g" myfile.txt

This will replace all the spaces in myfile.txt by a \

answered Aug 07 '17 at 11:38

Eos

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1
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ideasman42 · Answer 2 · 2017-08-07T22:01:22.183

I would suggest not simply replacing ' ' with '\ ' if you want to correctly quote paths.

Either:

Use nul terminators (-print0 argument to find)
Quote the paths using printf.

While not exactly what your asking for, correct path quoting can be done using printf '%q', eg:

FILENAMES="$(
    find -maxdepth 1 -not -path './.*' -type f -print0 |
    xargs -0 printf '%q\n'
)"

This is useful because it means other strange characters in file paths wont cause issues later on.

If some tricky person runs touch "foo\ bar.txt" for example :)

Sakis · Answer 3 · 2017-08-07T11:53:03.527

0

One way to do it is to execute the tar utility from find itself:

find -maxdepth 1 -not -path './.*' -type f -exec tar --exclude='archive.tar.bz2' -cvpjf archive.tar.bz2 "{}" +

edited Aug 07 '17 at 11:53

answered Aug 07 '17 at 11:41

Sakis

91
3

score 0 · Answer 4 · answered Aug 07 '17 at 11:50

0

FILENAMES="$(find -maxdepth 1 -not -path './.*' -type f -printf  "'"%f"'")"

Print each filename surrounded by single quotations.

answered Aug 07 '17 at 11:50

Raman Sailopal

12,320
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chepner · Answer 5 · 2017-08-07T12:33:43.713

Don't store a list of file names in a regular parameter. Use an array parameter instead. You don't need find either; a simple glob will match the same files.

filenames=( * )  # assuming there are no subdirectories in the current directory

To exclude directories (and other non-regular files), use a shell loop:

filenames=()
for f in *; do
    [[ -f $f ]] && filenames+=("$f")
done

Once the array is populated, use it as

tar --exclude='archive.tar.bz2' -cvpjf archive.tar.bz2 "${filenames[@]}"

If you had a more complex call to find, I would simply pipe the null-terminated list of found file names directory to tar without storing them first (assuming GNU tar, anyway):

find ... -print0 | tar --null -T - --exclude 'archive.tar.bz2' -cvpjf archive.tar.bz2

Replacing ' ' with '\ ' in bash

5 Answers5