How do you pipe input through grep to another utility?

Question

I am using \'tail -f\' to follow a log file as it\'s updated; next I pipe the output of that to grep to show only the lines containing a search term (\"org.springframework\"

Answer 1

Assuming GNU grep, add --line-buffered to your command line, eg.

tail -f logfile | grep --line-buffered org.springframework | cut -c 25-

Edit:

I see grep buffering isn't the only problem here, as cut doesn't allow linewise buffering.

you might want to try replacing it with something you can control, such as sed:

tail -f logfile | sed -u -n -e '/org\.springframework/ s/\(.\{0,25\}\).*$/\1/p'

or awk

tail -f logfile | awk '/org\.springframework/ {print substr($0, 0, 25);fflush("")}'