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Top Forums Shell Programming and Scripting How to tail sed and awk in one line? Post 302983564 by rbatte1 on Thursday 13th of October 2016 05:44:56 AM
Old 10-13-2016
Regarding the while true loop, are you concerned that the log file might be rotated/aged/re-written/whatever? If so, does your version of tail have the -F or --retry flags? These will keep looking for the file if it becomes inaccessible, so you keep reading the new log files that are created by normal ageing processes.

The alternate would be that you would have to have some way to terminate your tail and then restart it, all within the while true loop.


Can you put this code into context as to why you have written it like this so far. I'm sure we can help you to find a solution.



Kind regards,
Robin
 

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TAIL(1) 							   User Commands							   TAIL(1)

NAME
tail - output the last part of files SYNOPSIS
tail [OPTION]... [FILE]... DESCRIPTION
Print the last 10 lines of each FILE to standard output. With more than one FILE, precede each with a header giving the file name. With no FILE, or when FILE is -, read standard input. Mandatory arguments to long options are mandatory for short options too. -c, --bytes=K output the last K bytes; or use -c +K to output bytes starting with the Kth of each file -f, --follow[={name|descriptor}] output appended data as the file grows; an absent option argument means 'descriptor' -F same as --follow=name --retry -n, --lines=K output the last K lines, instead of the last 10; or use -n +K to output starting with the Kth --max-unchanged-stats=N with --follow=name, reopen a FILE which has not changed size after N (default 5) iterations to see if it has been unlinked or renamed (this is the usual case of rotated log files); with inotify, this option is rarely useful --pid=PID with -f, terminate after process ID, PID dies -q, --quiet, --silent never output headers giving file names --retry keep trying to open a file if it is inaccessible -s, --sleep-interval=N with -f, sleep for approximately N seconds (default 1.0) between iterations; with inotify and --pid=P, check process P at least once every N seconds -v, --verbose always output headers giving file names --help display this help and exit --version output version information and exit If the first character of K (the number of bytes or lines) is a '+', print beginning with the Kth item from the start of each file, other- wise, print the last K items in the file. K may have a multiplier suffix: b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y. With --follow (-f), tail defaults to following the file descriptor, which means that even if a tail'ed file is renamed, tail will continue to track its end. This default behavior is not desirable when you really want to track the actual name of the file, not the file descrip- tor (e.g., log rotation). Use --follow=name in that case. That causes tail to track the named file in a way that accommodates renaming, removal and creation. GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report tail translation bugs to <http://translationproject.org/team/> AUTHOR
Written by Paul Rubin, David MacKenzie, Ian Lance Taylor, and Jim Meyering. COPYRIGHT
Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. SEE ALSO
The full documentation for tail is maintained as a Texinfo manual. If the info and tail programs are properly installed at your site, the command info coreutils 'tail invocation' should give you access to the complete manual. GNU coreutils 8.22 June 2014 TAIL(1)
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