Read filenames with embedded whitespace into an array in a shell script - arrays

Question

Basically I'm searching for a multi-word file which is present in many directories using find command and the output is stored on to a variable vari
vari = `find -name "multi word file.xml"
When I try to delete the file using a for loop to iterate through.,
for file in ${vari[#]}
the execution fails saying.,
rm: cannot remove `/abc/xyz/multi':: No such file or directory
Could you guys please help me with this scenario??

Answer 1

If you really need to capture all file paths in an array up front (assumes bash, primarily due to use of arrays and process substitution (<(...))[1]; a POSIX-compliant solution would be more cumbersome[2]; also note that this is a line-based solution, so it won't handle filenames with embedded newlines correctly, but that's very rare in practice):
# Read matches into array `vari` - safely: no word splitting, no
# globbing. The only caveat is that filenames with *embedded* newlines
# won't be handled correctly, but that's rarely a concern.
# bash 4+:
readarray -t vari < <(find . -name "multi word file.xml")
# bash 3:
IFS=$'\n' read -r -d '' -a vari < <(find . -name "multi word file.xml")
# Invoke `rm` with all array elements:
rm "${vari[#]}" # !! The double quotes are crucial.
Otherwise, let find perform the deletion directly (these solutions also handle filenames with embedded newlines correctly):
find . -name "multi word file.xml" -delete
# If your `find` implementation doesn't support `-delete`:
find . -name "multi word file.xml" -exec rm {} +
As for what you tried:
vari=`find -name "multi word file.xml"` (I've removed the spaces around =, which would result in a syntax error) does not create an array; such a command substitution returns the stdout output from the enclosed command as a single string (with trailing newlines stripped).
By enclosing the command substitution in ( ... ), you could create an array:
vari=( `find -name "multi word file.xml"` ),
but that would perform word splitting on the find's output and not properly preserve filenames with spaces.
While this could be addressed with IFS=$'\n' so as to only split at line boundaries, the resulting tokens are still subject to pathname expansion (globbing), which can inadvertently alter the file paths.
While this could also be addressed with a shell option, you now have 2 settings you need to perform ahead of time and restore to their original value; thus, using readarray or read as demonstrated above is the simpler choice.
Even if you did manage to collect the file paths correctly in $vari as an array, referencing that array as ${vari[#]} - without double quotes - would break, because the resulting strings are again subject to word splitting, and also pathname expansion (globbing).
To safely expand an array to its elements without any interpretation of its elements, double-quote it: "${vari[#]}"
[1]
Process substitution rather than a pipeline is used so as to ensure that readarray / read is executed in the current shell rather than in a subshell.
As eckes points out in a comment, if you were to try find ... | IFS=$'\n' read ... instead, read would run in a subshell, which means that the variables it creates will disappear (go out of scope) when the command returns and cannot be used later.
[2]
The POSIX shell spec. supports neither arrays nor process substitution (nor readarray, nor any read options other than -r); you'd have to implement line-by-line processing as follows:
while IFS='
' read -r vari; do
pv vari
done <<EOF
$(find . -name "multi word file.xml")
EOF
Note the require actual newline between IFS=' and ' in order to assign a newline, given that the $'\n' syntax is not available.

Answer 2

Here are a few approaches:
# change the input field separator to a newline to ignore spaces
IFS=$'\n'
for file in $(find . -name '* *.xml'); do
ls "$file"
done
# pipe find result lines to a while loop
IFS=
find . -name '* *.xml' | while read -r file; do
ls "$file"
done
# feed the while loop with process substitution
IFS=
while read -r file; do
ls "$file"
done < <(find . -name '* *.xml')
When you're satisfied with the results, replace ls with rm.

Answer 3

The solutions are all line-based solutions. There is a test environment at bottom for which there is no known solution.
As already written, the file could be removed with this tested command:
$ find . -name "multi word file".xml -exec rm {} +
I did not manage to use rm command with a variable when the path or filename contains \n.
Test environment:
$ mkdir "$(printf "\1\2\3\4\5\6\7\10\11\12\13\14\15\16\17\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37\40\41\42\43\44\45\46\47testdir" "")"
$ touch "multi word file".xml
$ mv *xml *testdir/
$ touch "2nd multi word file".xml ; mv *xml *testdir
$ ls -b
\001\002\003\004\005\006\a\b\t\n\v\f\r\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037\ !"#$%&'testdir
$ ls -b *testdir
2nd\ multi\ word\ file.xml multi\ word\ file.xml