db.sh

#!/bin/bash
HEAD_LENGTH=5
TAIL_LENGTH=134
declare -A db

db[version]="0.0.6" # Database values
db[navn]="Marco"
db[kage]="sandt"



                                                                                                                                         
function get {                                                                                                                                             
    if [[ $# -le 0 ]]                                                                                                                                      
    then                                                                                                                                                   
        echo "Error: expected one or more key names"                                                                                                       
        exit 1                                                                                                                                             
    fi                                                                                                                                                     
                                                                                                                                                           
    for key in $@                                                                                                                                          
    do                                                                                                                                                     
        value=${db[$key]}                                                                                                                                  
                                                                                                                                                           
        if [[ -z $value ]]                                                                                                                                 
        then                                                                                                                                               
            echo "Error: Key '$key' not present."                                                                                                          
            exit 1                                                                                                                                         
        fi                                                                                                                                                 
                                                                                                                                                           
        echo "$value"                                                                                                                                      
    done                                                                                                                                                   
} 

function has {
    if [[ $# -eq 0 ]]
    then
        echo "Error: expected one or more key names"
        exit 1
    fi

    keys=$@

    if [[ $1 == "all" ]]
    then
        keys=${db[@]}
    fi

    for key in $keys
    do
        if [[ -z ${db[$key]} ]]
        then
            echo "false"
        else
            echo "true"
        fi
    done
}

function update {
    cat $0 | head -n $HEAD_LENGTH > $0.tmp

    for key in ${!db[@]}
    do
        echo "db[$key]=\"${db[$key]}\"" >> $0.tmp
    done

    cat $0 | tail -n $TAIL_LENGTH >> $0.tmp
    chmod u+x $0.tmp
    mv $0.tmp $0
}

function set {
    if [[ $# -ne 2 ]]
    then
        echo "Error: expected just key and value"
        exit 1
    fi
    
    key=$1
    value=$2

    db[$key]="$value"
    update
    echo "ok"
}

function del {
    if [[ $# -eq 0 ]]
    then
        echo "Error: expected keys"
        exit 1
    fi
    
    keys=$@

    if [[ $1 == "all" ]]
    then
        keys=${db[@]}
    fi
    
    for key in $keys
    do
        unset db[$key]
    done

    update
    echo "ok"
}

function help {
    echo "Commands:"
    printf "\tget <keys..>\tReturns the values of the given keys\n"
    printf "\thas <keys..>\tReturns whether the keys are present\n"
    printf "\tset <key> <val>\tSets the given key to the given value\n"
    printf "\tdel <keys..>\tDeltes the given keys\n"
}

case "$1" in
    get)
        get ${@:2}
        exit $?
        ;;
    has)
        has ${@:2}
        exit $?
        ;;
    set)
        set ${@:2}
        exit $?
        ;;
    del)
        del ${@:2}
        exit $?
        ;;
    help)
        help
        exit $?
        ;;
    *)
        echo "Error: unknown command '$1', use 'db help'"
        exit 1
esac