Tail a log and replace according to a sed pattern

tail -F logfile|while read l; do sed 's/find/replace/g' <<< $l; done
Tails a log and replaces it line-by-line according to whatever you want to replace. Useful if the file writing to the log can't be modified, so you need to modify its output instead.
Sample Output 
echo "line1
find
line2" >> logfile

Output:
line1
replace
line2

1
By: tyzbit
2020-08-07 12:26:39
read sed tail sed tail tail -f
3
Submit An Alternative

What Others Think

What's the difference between this and the following? tail -F logfile | sed 's/unix/linux/g' I tried both, and they seemed to behave identically.
jcholewa · 280 weeks and 6 days ago
The article has outstanding content. All information in the article is very delicate. I will keep waiting for your posts.
saichinni · 271 weeks and 5 days ago
cool
Manicopus · 264 weeks and 4 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

You must be signed in to comment.

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Similar Commands

tail from the last occurrence of a pattern to the end of the (log) file

tail, with specific pattern colored

tail, with specific pattern colored

In-Place search/replace with datestamped backup

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: