tar exclude folders ignored when called from bash function

Question

The following code didn't work, exclude folders are ignored by tar. How can I fix that ? Please note I may have multiple exclude folders and multiple folders to backup.

date=`date +%Y%m%d`

# tar_create function
# ARG1=<filename_to_write> ARG2=<exclusions> ARG3=<folders>
tar_create () {
    exclude_options=()
    if [ ${#exclude[@]} -ne 0 ]; then
        for x in "${2[@]}"; do
            exclude_options+=(--exclude="$x")
        done
    fi
    echo "$(date '+%Y%m%d:%H:%M:%S'): Running tar czvpf "${1}" "${exclude_options[@]}" ${@:3}"
    tar czvpf "${1}" "${exclude_options[@]}" ${@:3} 2>&1 > "${1}.txt"
    ret=$?
    if [ $ret != 0 ] && [ $ret != 1 ]; then
        echo "$(date '+%Y%m%d:%H:%M:%S'): Error: tar returned $ret for ${1}"
        echo "$(date '+%Y%m%d:%H:%M:%S'): Error: tar returned $ret for ${1}" >> "${1}-errors.txt"
    fi
    echo "$(date '+%Y%m%d:%H:%M:%S'): End tar czvpf "${1}" "${exclude_options[@]}" ${@:3} : return $ret"
}

# do_backup function
# ARG1=<filename_to_write> ARG2=<root folder to backup> ARG3=<exclusions in tar format> ARG4=<folders to backup>
do_backup () {
    if [ ! -d "$(dirname "${1}")" ] || [ ! -w "$(dirname "${1}")" ]; then
        echo "Folder ${1} doesn't exist or isn't writable, can't write backup files" >> backup-error.log
    fi
    if [ ! -d "$(dirname "${2}")" ]; then
        echo "Folder to backup ${1} doesn't exist" >> backup-error.log
    fi

    declare -a exclude=("${!3}")
    declare -a folders=("${!4}")
    declare -a all=("${exclude[@]}" "${folders[@]}")

    echo "cd ${2}"
    cd "${2}"
    echo "tar_create ${1} ${3} ${4}"
    tar_create "${1}" "${3}" "${4}"
}
exclude=( './photos' './videos' './archives' )
folders=( './' )
do_backup "/hdd/backup-$date.tar.gz" "/home/datastorez" "${exclude[@]}" "${folders[@]}"

If the tar paths are absolute, the excludes have to be absolute. If the paths are relative, i.e. ".", then the excludes must be of the form "./{pattern}". — Eric Marceau
– Eric Marceau, Commented Feb 25, 2023 at 23:07
Should you have the "!" in the lines ... declare -a exclude=("${!3}") ...and ... declare -a folders=("${!4}") ? — Eric Marceau
– Eric Marceau, Commented Feb 25, 2023 at 23:11

Freddy · Accepted Answer · 2023-02-26 01:38:57Z

This is a minimal example how you could use a function to create the tar file. In your code it's not possible to distinguish the exclusions and the backup folders when passed to the function as arguments. Arrays are expanded to multiple words using the "${name[@]}" syntax.

Example: If the exclude array is empty, argument $3 in do_backup would be the first element of folders. If there are two items in the exclude array, then the first element of folders would be $5.

Changes:

$1: name of the backup
$2: directory to switch to
$3: name of the excludes array variable. In the function we declare a variable using the nameref attribute (-n) to access the array elements.
$4-$n: directories to backup

# ARG1=<filename_to_write> ARG2=<change_to_dir> ARG3=<name_of_exclude_array> ARG4...=<directories>
tar_create () {
    local -n excl=$3
    local exclude_options=()
    for i in "${excl[@]}"; do
        exclude_options+=( --exclude "$i" )
    done

    tar czvpf "$1" -C "$2" "${exclude_options[@]}" "${@:4}"
}

exclude=( ./photos ./videos ./archives )
dirs=( ./ )
tar_create /hdd/backup-$(date +%Y%m%d).tar.gz /home/datastorez exclude "${dirs[@]}"

Stack Exchange Network

tar exclude folders ignored when called from bash function

1 Answer 1

You must log in to answer this question.

Hot Network Questions

tar exclude folders ignored when called from bash function

1 Answer 1

You must log in to answer this question.

Related

Hot Network Questions