CODEWITHSUNDEEP
linuxbashunixsh
Vladimir Todorov
Vladimir Todorov

Reputation: 79

Bash - replace in file strings from first array with strings from second array

I have two arrays. The first one is filled with values greped from the file that I want to replace with the new ones downloaded.

Please note that I don't know exactly how the first array will look like, meaning some values will have _, other - and some won't have any of that and immediately after the name will be placed : (colon).

Example arrays:

array1:

[account:123 shoppingcart-1:123 notification-core_1:123 notification-dispatcher_core_1:123 notification-dispatcher-smschannel_core_1:123]

array2:

[account_custom_2:124 shoppingcart_custom_2:124 notification_custom_2:124 notification-dispatcher_custom_2:124 notification-dispatcher-smschannel_custom_2:124]

Those arrays are the only example, there are more than 50 values to replace.

I am doing a comparison of every item in the second array with every item in the first array as shown below:

file_name="<path_to_file>/file.txt"
for i in "${!array1[@]}"
do
        for j in "${!array2[@]}"
        do
                array_2_base="`echo ${array2[$j]} | awk -F_ '{print $1}'`"
                if [[ "${array1[$i]}" == *"$array_2_base"* ]]
                then
                        sed -i "s=${array1[$i]}=${array2[$j]}=g" $file_name
                 fi
        done
done

Here I substring only the first part for every item in the second array so I can compare it with the item in the first array.

e.g. account_custom_2:124 -> account or notification-dispatcher_custom_2:124 -> notification-dispatcher.

This works nice but I encounter problem when notification is in notification-core_1:123 and notification-dispatcher_core_1:123 and notification-dispatcher-smschannel_core_1:123.

Can you please give advice on how to fix this or if you can suggest another approach to this?

Upvotes: 0

Views: 127

Answers (3)

tshiono
tshiono

Reputation: 22062

The point is the base of array2 element may include other element as a substring and will cause an improper replacement depending on the order of matching. To avoid this, you can sort the array in descending order so the longer pattern comes first.

Assuming the strings in the arrays do not contain tab characters, would you please try:

file_name="<path_to_file>/file.txt"
array1=(account:123 shoppingcart-1:123 notification-core_1:123 notification-dispatcher_core_1:123 notification-dispatcher-smschannel_core_1:123)
array2=(account_custom_2:124 shoppingcart_custom_2:124 notification_custom_2:124 notification-dispatcher_custom_2:124 notification-dispatcher-smschannel_custom_2:124)

# insert the following block to sort array2 in descending order
array2=( $(for j in "${array2[@]}"; do
    array_2_base=${j%%_*}
    printf "%s\t%s\n" "$array_2_base" "$j"
done | sort -r | cut -f2-) )

# the following code will work "as is"
for i in "${!array1[@]}"
do
    for j in "${!array2[@]}"
    do
        array_2_base="`echo ${array2[$j]} | awk -F_ '{print $1}'`"
        if [[ "${array1[$i]}" == *"$array_2_base"* ]]
        then
            sed -i "s=${array1[$i]}=${array2[$j]}=g" "$file_name"
            delete="${array1[$i]}"
            array1=( "${array1[@]/$delete}" )
        fi
    done
done

The script above will be inefficent in execution time due to the repetitive invocation of sed -i command.
The script below will run faster by pre-generating the sed script and executing it just once.

file_name="<path_to_file>/file.txt"
array1=(
    account:123
    shoppingcart-1:123
    notification-core_1:123
    notification-dispatcher_core_1:123
    notification-dispatcher-smschannel_core_1:123
)
array2=(
    account_custom_2:124
    shoppingcart_custom_2:124
    notification_custom_2:124
    notification-dispatcher_custom_2:124
    notification-dispatcher-smschannel_custom_2:124
)

while IFS=$'\t' read -r base a2; do     # read the sorted list line by line
    for a1 in "${array1[@]}"; do
        if [[ $a1 == *$base* ]]; then
            scr+="s=$a1=$a2=g;"         # generate sed script by appending the "s" command
            continue 2
        fi
    done
done < <(for j in "${array2[@]}"; do
    array_2_base=${j%%_*}               # substring before the 1st "_"
    printf "%s\t%s\n" "$array_2_base" "$j"
                                        # print base and original element side by side
done | sort -r)

sed -i "$scr" "$file_name"              # execute the replacement at once

Upvotes: 1

Ivan
Ivan

Reputation: 7317

If number of items in your arrays are equal then you can process them in one loop

for i in "${!array1[@]}"; {
    value=${array1[$i]}
    new_value=${array2[$i]}
    sed -i "s/$value/$new_value/" file
}

Upvotes: 1

Vladimir Todorov
Vladimir Todorov

Reputation: 79

I found a way to fix this.

I am deleting string from the first array once replaced.

file_name="<path_to_file>/file.txt"
for i in "${!array1[@]}"
do
        for j in "${!array2[@]}"
        do
                array_2_base="`echo ${array2[$j]} | awk -F_ '{print $1}'`"
                if [[ "${array1[$i]}" == *"$array_2_base"* ]]
                then
                        sed -i "s=${array1[$i]}=${array2[$j]}=g" $file_name
                        delete="${array1[$i]}"
                        array1=( "${array1[@]/$delete}" )
                 fi
        done
done

Upvotes: 0

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