Tailf:
tailf will print out the last 10 lines of a file and then wait for the file to grow. It is similar to tail -f but does not access the file when it is not grow-ing. This has the side effect of not updating the access time for the file, so a filesystem flush does not occur periodically when no log activity is happening.
tailf is extremely useful for monitoring log files on a laptop when logging is infrequent and the user desires that the hard disk spin down to conserve battery life.
Example: # tailf /var/log/squid/access.log
Similarly you can watch the same log file using -f argument
Example: # tail -f /var/log/squid/access.log
1 comments:
The only caveat is that tail -f is not suitable for long-term use, as logrotate will rotate the watched file to log.n+1. Since the read syscall is linked to the inode and not the filename, your app will never know the file was renamed and you will be waiting patiently for new data on a stale file.
You can use watch to periodically reiterate the tail command, or use something like xconsole to read a FIFO
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