How to remove all strings from array that end with a specific character

Question

I have an array containing a list of file paths within different levels of directories. I want to filter that array to only files,meaning those that end with an / should remain in the array. All paths are no real paths on my file system I could check the type using OS tools for directories/files.

I have an array with following strings:

file-a
dir/
dir/file-b
dir/dir-2/
dir/dir-2/file-c

And want to filter it to the following strings (no directories):

file-a
dir/file-b
dir/dir-2/file-c

I tried it with the following but that removes all paths including a /, resulting in file-a being the only remain.

FILES_ARRAY=( ${FILES_ARRAY[@]//*\/} )

I tried to add an $ (as common in regex syntax) to denote the end which does not remove anything from the array.

FILES_ARRAY=( ${FILES_ARRAY[@]//*\$/} )

`${FILES_ARRAY[@]//*\/}` is not a regex, this syntax is specific to Bash string manipulation using globs. — Wiktor Stribiżew, Sep 20 '20 at 12:29

markp-fuso · Answer 1 · 2020-12-27T15:24:22.573

Two different solutions depending on what filter means:

1 - remove the directory entries from the array:

declare -a FILES_ARRAY=([0]="file-a" [1]="dir/" [2]="dir/file-b" [3]="dir/dir-2/" [4]="dir/dir-2/file-c")
echo "++++++++++++++ array - before"
printf "%s\n" ${FILES_ARRAY[@]}

for i in ${!FILES_ARRAY[@]}
do
    [[ "${FILES_ARRAY[${i}]}" == */ ]] && unset FILES_ARRAY[${i}]       # remove directory from array
done

echo "++++++++++++++ array - after"
printf "%s\n" ${FILES_ARRAY[@]}

This generates:

++++++++++++++ array - before
file-a
dir/
dir/file-b
dir/dir-2/
dir/dir-2/file-c
++++++++++++++ array - after
file-a
dir/file-b
dir/dir-2/file-c

2 - leave the directory entries in the array but don't display them; we can re-use the above code with a change to the body of the for loop:

declare -a FILES_ARRAY=([0]="file-a" [1]="dir/" [2]="dir/file-b" [3]="dir/dir-2/" [4]="dir/dir-2/file-c")
echo "++++++++++++++ array"
printf "%s\n" ${FILES_ARRAY[@]}

echo "++++++++++++++ display"
for i in ${!FILES_ARRAY[@]}
do
    [[ "${FILES_ARRAY[${i}]}" != */ ]] && echo "${FILES_ARRAY[${i}]}"   # only display non-directory entries
done

This also generates:

++++++++++++++ array
file-a
dir/
dir/file-b
dir/dir-2/
dir/dir-2/file-c
++++++++++++++ display
file-a
dir/file-b
dir/dir-2/file-c

score 0 · Answer 2 · edited Sep 20 '20 at 13:33

You can use

FILES_ARRAY=(file-a dir/ dir/file-b dir/dir-2/ dir/dir-2/file-c)
NEW_FILES_ARRAY=()
for (( i=0; i<${#FILES_ARRAY[@]}; i++ )); do 
  if ! [[ "${FILES_ARRAY[$i]}" == */ ]]; then
    NEW_FILES_ARRAY+=("${FILES_ARRAY[$i]}");
  fi
done
FILES_ARRAY=("${NEW_FILES_ARRAY[@]}")

printf '%s\n' ${FILES_ARRAY[@]}

Output:

file-a
dir/file-b
dir/dir-2/file-c

See an online Bash demo.

NOTES:

for (( i=0; i<${#FILES_ARRAY[@]}; i++ )); do ... done iterates over the FILES_ARRAY length, i is assigned indices of the array elements
if ! [[ "${FILES_ARRAY[$i]}" == */ ]] checks if the current element does not end with / (* matches any amount of any chars and / matches /, the glob pattern always requires entire string match, no need for $) and
NEW_FILES_ARRAY+=("${FILES_ARRAY[$i]}"); adds the current item to the NEW_FILES_ARRAY array.
FILES_ARRAY=("${NEW_FILES_ARRAY[@]}") reassigns the original variable so that it holds the filtered elements

That example does not completely work because we are altering the array while iterating it. This way, the last entry is not handled and `dir/dir-2/file-c` is missing. — Sebastian Barth, Sep 20 '20 at 13:02

Ivan · Answer 3 · 2020-09-21T07:39:59.947

0

This awk command may help, but it'll fail with spaces in paths

new_arr=($(awk '{for (i=1; i<=NF; i++) if ($i !~ /\/$/) {print $i}}' <<< "${arr[@]}"))

edited Sep 21 '20 at 07:39

answered Sep 21 '20 at 07:29

Ivan

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How to remove all strings from array that end with a specific character

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