To replace a immediate text after pattern match in Linux shell using sed

Question

Content of a json file

"iso_checksum": "md5:32fdf4fef4ef"

I have stored value of new checksum in a variable v = "4dfv45ffdf"

I want to replace the value after md5: from 32fdf4fef4ef to 4dfv45ffdf after replace above line in the file should like

"iso_checksum": "md5:4dfv45ffdf"

32fdf4fef4ef is not fixed value so we can not just replace like below

sed -i 's/32fdf4fef4ef/4dfv45ffdf/' file

4dfv45ffdf this is also not fixed value so kept in as $v

Can any please help me to perform the above task

See https://stackoverflow.com/questions/45464280/, https://stackoverflow.com/q/50265987 and https://stackoverflow.com/questions/65090642/, etc. — Wiktor Stribiżew, Apr 08 '22 at 07:17
One-liner: `v="4dfv45ffdf"; echo '"iso_checksum": "md5:32fdf4fef4ef"' | sed "s/\"md5:[^\"]*\"/\"md5:$v\"/g"` — SergA, Apr 08 '22 at 07:26
Does this answer your question? [Need sed command to replace JSON property value](https://stackoverflow.com/questions/65090642/need-sed-command-to-replace-json-property-value) — Wiktor Stribiżew, Apr 08 '22 at 07:41
Below command solved my purpose Thanks Wiktor Stribiżew sed "/\"name\":/s/$^[^:]*[:][ ]$.*$/\1\"$username\",/" — pravin kumar, Apr 08 '22 at 09:28

score 1 · Answer 1 · edited Apr 26 '22 at 14:24

1

Correct answer as below

y="4dfv45ffdf"
sed "/\"iso_checksum\":/s/\(^[^:]*[:][ ]\).*$/\1\"md5:$y\",/" file.json

edited Apr 26 '22 at 14:24

RavinderSingh13

answered Apr 08 '22 at 09:32

pravin kumar

score 0 · Answer 2 · answered Apr 08 '22 at 07:56

0

I would use GNU AWK for this task following way

awk -v v="4dfv45ffdf" '{gsub("md5:[[:xdigit:]]+","md5:"v);print}' file.json

Explanation: replace every md5: followed by 1 or more base16-digits using md5: concatenated with value of v, print whole line.

answered Apr 08 '22 at 07:56

Daweo

2 Answers2