UNIX for Dummies Questions & Answers

Input File1 constatntly running and growing in size.

My Program Erorr ddmmyy hh:mm:ss My Program Error
**Port 123 terminated
**ID PIN 12345
Comamnd Successful
Command Terminated
Command Successful
Command Terminated
**My Program Erorr ddmmyy hh:mm:ss My Program Error
**Port 345 terminated
**ID PIN 67890
Comamnd Successful
Command Terminated
Command Successful
Command Terminated
**My Program Erorr ddmmyy hh:mm:ss My Program Error
**Port 678 terminated
**ID PIN 13579
Comamnd Successful
Command Terminated
Command Successful
Command Terminated


I periodically copy file1, to file2 and then run awk script to display "Program Errors" and then mailx to my inbox.

This part is working fine, however since the input file1 is constantly running and growing in size, is there a way to copy
only the last part that have been updated since last copy was run.
**I can add a time stamp to the file's header or footer if that can make things easier.
Thank you

start with tail -f. It is meant to do exactly what you want.

Code:

tail -f logfile  | [some code here]

Tail command will not work since I don't know how many lines are in the file.
The file is continuously growing, and sometime there are 100 lines per minute, sometimes 300 or more.

You don't have to, because tail -f never quits -- when it hits the end of file, it waits for more data. Whenever the length of the file changes, it will print out what was added. If the file is truncated, it ought to start over from the beginning, too.