Question

NGINX rewrite script

Posted on December 19, 2021
Nginx Linux Commands
Asked by MichalGiza

Hi, Sometimes I’ve to add hundreds of redirects to my NGINX server block. Such a script could definitely make my work easier. I didn’t find ready-made solutions. I’m writing a script that gets addresses from a file and creates rewrite rules for NGINX based on it. The file just contains the old address and the new address separated by a space, for example:

old.html new.html
oldpage newpage
error.php 404

So I should get something like this:

rewrite ^/old.html$ https://domain.com/new.html permanent;
rewrite ^/oldpage$ https://domain.com/newpage permanent;
rewrite ^/error.php$ https://domain.com/404 permanent;

For now, my script looks like this:

if [ "$#" -eq 0 ]; then
    echo "Usage: ./rewrite.sh <domain> <file>"
    exit
else
    DOMAIN=${1}
    FILE=${2}
fi

sed -e 's/$/ permanent;/' -i $FILE #end of each line

It does nothing but add “permanent ;” to the end of each line. How do I add “rewrite ^/” to the beginning of each line? I tried this way, but it doesn’t work :

REW=“rewrite ^/” sed -i -e “s/^/‘${REW}’/” $FILE

I also have no idea how to add “$ https://domain.com/” in the beginning of the new address.

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Bobby Iliev

Site Moderator

• December 19, 2021

Accepted Answer

Hi there,

There are probably multiple ways to do it, but I would personally use a for loop to loop through each of the lines fo the file and then use printf to construct the redirect rule as follows:

#!/bin/bash

if [ "$#" -eq 0 ]; then
    echo "Usage: ./rewrite.sh <domain> <file>"
    exit
else
    DOMAIN=${1}
    FILE=${2}
fi

OLDIFS="$IFS"
IFS=$'\n' # bash specific
for line in $(cat ${FILE})
do
    old=$(echo $line | awk '{print $1}')
    new=$(echo $line | awk '{print $2}')
    printf "rewrite ^/%s$ https://${DOMAIN}/%s permanent;\n" "$old" "$new"
done

IFS="$OLDIFS"

Quick rundown:

It sets the IFS (Internal field separator) variable as separators so that the for loop would go through each separate line
Then we start the for loop
Using awk we get the old and the new URLs as we follow the conversion that the first one is the old URL and the second is the new one
Finally, we use the printf to construct the rules

This will print the results on the screen and you can copy them from there. Or alternatively, when running the script you could send the STDOUT to a file: bash script.sh domain.com file.txt > new_rules.txt.

Hope that this helps! Best, Bobby