CODEWITHSUNDEEP
regexmacosbashunixsed
user3363550
user3363550

Reputation: 49

How can i replace the existing mac add with a new mac address using sed

I have this existing pattern:

ethernet0.generatedAddress = "00:50:56:bf:71:06"

I need to replace a mac address in the above expression with a new mac address using a sed pattern. Note: The mac-address that needs to replaced is not same everytime.

I tried this sed expression , but no luck..

sed 's/ethernet0.generatedAddress.*=.*\"([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}/ethernet0.generatedAddress = \"00:16:3e:5e:1d:01'

Thanks in Advance

Upvotes: 1

Views: 822

Answers (2)

Jotne
Jotne

Reputation: 41460

Why not use awk? It gives simple and easy to understand solution.

cat file
some data
ethernet0.generatedAddress = "00:50:56:bf:71:06"
more data


mac="ab:11:23:55:11:cc"


awk -v m="$mac" -F' "|"' '/ethernet0.generatedAddress/ {$2="\""m"\""}1' file
some data
ethernet0.generatedAddress = "ab:11:23:55:11:cc"
more data

It search for ethernet0.generatedAddress, if found, replace field #2 separated by " with new mac.

If one extra space is not problem, this would be more clean:

awk -v m="$mac" -F\" '/ethernet0.generatedAddress/ {$2=FS m FS}1' file
some data
ethernet0.generatedAddress =  "ab:11:23:55:11:cc"
more data

Or this:

awk -v m="\"$mac\"" -F\" '/ethernet0.generatedAddress/ {$2=m}1' file

Upvotes: 1

hex494D49
hex494D49

Reputation: 9235

Pattern:

([a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2})

Or the following one if uppercase letters are used

([a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2})

Replacement:

new_mac_address // for instance 00:f6:a0:ff:f1:06

Side note: As has been pointer in the comments below, escape parentheses and curly brackets if needed or use -r option

Using sed it would be something like this (just tested)

sed -r 's/(.*)([a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2}:[a-zA-Z0-9]{2})(.*)/\1\NEW_MAC_ADDRESS\3/g' file.txt

Use -i option in addition if you want to replace the file on-the-fly

Content of the tested file (file.txt)

something before ethernet0.generatedAddress = "00:50:56:bf:71:06" and something after

Demo

Upvotes: 2

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