Shell Programming and Scripting

Hi
I am new to writing script and want to use a Bash Piped while-read and read from user input.

if something happens on server.log then do while loop or if something happend on user input then do while loop.

Pseudocode something like:
tail -n 3 -f server.log | while read serverline || read -p # -e promptline
do
if something happend on promptline then do this
if something happend serverline then do this

I appreciate all help.
Thanks

Read user input from /dev/tty, to avoid accidentally reading input from the pipe or file instead. /dev/tty will always be the current terminal, if any.

Code:

... | while read LINE
do
        printf "prompt: "
        read USERINPUT </dev/tty
done

Thanks, will this lock the while loop and wait for user input? I want the script to react and run the wile loop if something happens in the server.log file as well.

Yes, it will block.

Since it's bash, you could have it time out eventually if the user doesn't type anything ( read -t 1 userinput < /dev/tty )

I can not get it to work as it builds on that it comes data on file 'server.log' for the program to get to the prompt and there is no steady stream of data on that file.

I don't think I really understand what you're trying to do, then. Could you give a little pseudocode?

No worries, I explain in greater detail. It might very well be that I do not understand you.
I have a process A that depends on two processes.
Process B is the one assigned to the file server.log
Process C is if a user writes something

If data comes from B or C should process A run
Pseudocode something like:

Code:

tail -n 3 -f server.log | while read serverline || read userinput
do
if something happend on userinput then do this
if something happend serverline then do this

I do not know how to write something like this:

Code:

tail -n 3 -f server.log | while read serverline | while read -t 1 userinput < /dev/tty

A problem with another solution like this is that it is locked on the tail line

Code:

tail -n 3 -f server.log | while read serverline
do
        printf "prompt: "
        read -t 1 USERINPUT </dev/tty

And the same problem with a solution like this is that it is locked on the tail line

Code:

do
        printf "prompt: "
        read -t 1 USERINPUT </dev/tty
        tail -n 3 -f server.log | while read serverline
        do

I hope I explained my problem better and if not do not hesitate to ask again.