Replace all characters between two strings in a li

Question

This question already has an answer here:

• Substitute all characters between two strings by char 'X' using sed 3 answers

I want to change (via bash script using SED command) all the characters in between two given strings with an equal number of X characters. If say, the first string is %26Name%3d and the last sting is %26, then anything in between these two strings I want to replace with an equal number of X characters. I am reading a file in place. The file is roughly 1MB.

So

SOMETHING%26Name%3dTHISTEXTNEEDSTOBE%26ELSE

to

SOMETHING%26Name%3dXXXXXXXXXXXXXXXXX%26ELSE  

OR if start string is %26Last%3d and ending string is %26

something%26Last%3d%2%2%4%2%4%3%5%%2%2%2%26else  

to

something%26Last%3dXXXXXXXXXXXXXXXXXXXXX%26else  

I tried below using the sed command in my bash script but didn't worked perfectly.

file=mylog.log
myAnd=\\%26
myEqual=\\%3d
startList=Name\|Last
end_str="\%26"
search_str="$myAnd""(""$startList"")""$myEqual"

sed -i -E ':a; s/('"$search_str"'X*)[^X](.*'"$end_str"')/\1X\2/; ta' "$file"

PS startList=Name\|Last above declaration and also of myAnd and myEqual.

Example:

SOME%26Name%3dTHISTEXTNEEDSTOBE%26Last%3dDUTTA  
to  
SOME%26Name%3dXXXXXXXXXXXXXXXXX%26Last%3dXXXXX  

Answer 1

perl's s/// operator lets you evaluate perl code in the replacement part with the e flag

perl -e '
    my @strings = qw{
        SOMETHING%26Name%3dTHISTEXTNEEDSTOBE%26ELSE
        something%26Last%3d%2%2%4%2%4%3%5%%2%2%2%26else
    };
    my $start = q{%26(?:Name|Last)%3d};
    my $stop = q{%26};
    for my $str (@strings) {
        (my $copy = $str) =~ s/$start\K(.*?)(?=$stop)/"X" x length($1)/ge;
        print "$str\n$copy\n";
    }
'

SOMETHING%26Name%3dTHISTEXTNEEDSTOBE%26ELSE
SOMETHING%26Name%3dXXXXXXXXXXXXXXXXX%26ELSE
something%26Last%3d%2%2%4%2%4%3%5%%2%2%2%26else
something%26Last%3dXXXXXXXXXXXXXXXXXXXXX%26else

Answer 2

Hope this is what you are looking for.

As you have mentioned only the startList is different, I have framed the code to only vary this. Add the rest of the variables to the array in single quotes just like the two I have added.

Script:

file=/path/to/your/file
declare -a arr=('%26Name%3d' '%26Last%3d')
for i in "${arr[@]}";
do
sed -i -e :a -e "s/\($i[X]*\)[^X]\(.*%26\)/\1X\2/;ta" $file;
done

Detailed Session Output:

$ cat script.sh
file=/home/siju/Desktop/test
declare -a arr=('%26Name%3d' '%26Last%3d')
for i in "${arr[@]}";
do
sed -i -e :a -e "s/\($i[X]*\)[^X]\(.*%26\)/\1X\2/;ta" $file;
done
$ 
$ cat test
SOMETHING%26Name%3dTHISTEXTNEEDSTOBE%26ELSE  
something%26Last%3d%2%2%4%2%4%3%5%%2%2%2%26else 
$ 
$ ./script.sh 
$ cat test
SOMETHING%26Name%3dXXXXXXXXXXXXXXXXX%26ELSE  
something%26Last%3dXXXXXXXXXXXXXXXXXXXXX%26else 

Answer 3

Here is a sed solution:

sed -e :a -e 's/\(%26Name%3d[X]*\)[^X]\(.*%26\)/\1X\2/;ta'