"Shell script to tail a file with unknown numbers"

Post #303038662 by encrypt_decrypt on Tuesday 10th of September 2019 02:57:52 PM

Shell script to tail a file with unknown numbers

I would like to write script to tail a file for different environment
But the number of lines are keep changing
How can I write a script
For example:
env could : A, B or C
and log files could be a.log, b.log and c.log
with the number of lines can change
say sometimes it 100 last lines or 400 last lines or full log files

How to accomplish this using a script

thanks in advance

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TAIL(1) 						      General Commands Manual							   TAIL(1)

tail - deliver the last part of a file SYNOPSIS
tail [ +-number[lbc][rf] ] [ file ] tail [ -fr ] [ -n nlines ] [ -c nbytes ] [ file ] DESCRIPTION
Tail copies the named file to the standard output beginning at a designated place. If no file is named, the standard input is copied. Copying begins at position +number measured from the beginning, or -number from the end of the input. Number is counted in lines, 1K blocks or bytes, according to the appended flag or Default is -10l (ten ell). The further flag causes tail to print lines from the end of the file in reverse order; (follow) causes tail, after printing to the end, to keep watch and print further data as it appears. The second syntax is that promulgated by POSIX, where the numbers rather than the options are signed. EXAMPLES
tail file Print the last 10 lines of a file. tail +0f file Print a file, and continue to watch data accumulate as it grows. sed 10q file Print the first 10 lines of a file. SOURCE
/src/cmd/tail.c BUGS
Tails relative to the end of the file are treasured up in a buffer, and thus are limited in length. According to custom, option +number counts lines from 1, and counts blocks and bytes from 0. Tail is ignorant of UTF. TAIL(1)

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