CODEWITHSUNDEEP
shellunixscripting
Praveen Kumar
Praveen Kumar

Reputation: 45

Bash function not returning value properly

I don't know what is wrong with my function; it is not returning value properly.

function validate_directory_isempty     {
    retval=""

    NumOfFiles=`ls -l $input | egrep -c "^-"`

    if [ "$NumOfFiles" == "0" ];then
            retval=true

    else
            retval=false

    fi
    echo $retval
}


retval=$(validate_directory_isempty /opt/InstallationManager)
echo "retval : " $retval
if [ "$retval" == "true" ]; then
        echo ""
        echo "Installing Installation Manager"

#       Install_IM

else
        echo ""
        echo "DIRECTORY is not empty. Please make sure install location $DIRECTORY is empty before installing PRODUCT"

fi

Upvotes: 0

Views: 292

Answers (2)

Praveen Kumar
Praveen Kumar

Reputation: 45

i just replaced my script as below and it worked

removed the below commands retval=$(validate_directory_isempty /opt/InstallationManager) echo "retval : " $retval

added input=/opt/InstallationManager validate_directory_isempty

and it worked.

Thanks again for your valuable inputs

Upvotes: 0

glenn jackman
glenn jackman

Reputation: 247210

The idiomatic way to have a function return true or false is to use the return keyword. A return value of 0 means success, a non-zero value means failure. Also note that a function will return with a status of the last command executed if return is not present.

I would write your function like this

is_dir_empty() {
    shopt -s nullglob
    local -a files=( "$1"/* )
    (( ${#files[@]} == 0 ))
}

directory=/opt/InstallManager
if is_dir_empty "$directory"; then
    echo "$directory" is empty
fi

The first line sets a shell option that pattern matching no files expands to null instead of the pattern itself as a string.

The second line fills an array with the filenames in the given directory.

The last line tests the number of elements in the array. If zero entries, return success else return failure.

Upvotes: 1

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