CODEWITHSUNDEEP
awksed
Asad Javed
Asad Javed

Reputation: 57

Replace IP using AWK or SED

I have to replace an IP in a script so I used a variable to store the output of awk like for instance:

existing_ip=$(awk --field-separator '=' '/10.171.0.231/ { print $2; }' file.txt)

On the other hand I am also taking user input like:

read -p  "What is the IP address to be replace: " new_ip

echo -e "New IP: ${new_ip}"

Now in the next step I am facing an issue when I try to replace the IP with sed or awk command. I have tried using the below commands but none worked.

awk -v s="$existing_ip"  '{gsub(/10.171.[0-9].{1,3}.[0-9]/, s)}1'

sed -i "s/${existing_ip}/${new_ip}/g"

Help will be greatly appreciated.

Upvotes: 0

Views: 697

Answers (1)

The fourth bird
The fourth bird

Reputation: 163297

Apart from mentioned in the comment that you have to specify an input file, the pattern 10.171.[0-9].{1,3}.[0-9] can match for example 10a171b0cdef2 as you have to escape the dot to match it literally.

If you escape the dot, the quantifier {1,3} would go after matching a digit at the end. So you would match a single digit in the 3rd part, and 1-3 digits in the 4th part.

cat file.txt

This is ip 10.171.1.111 and this is ip 10.172.0.231

For example

existing_ip="10.171.0.231"
awk -v s="$existing_ip"  '{gsub(/10\.171\.[0-9]\.[0-9]{1,3}/, s)}1' file.txt

Output

This is ip 10.171.0.231 and this is ip 10.172.0.231

Upvotes: 1

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