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How to end tail-F in a shell script?
A shell script starting the Java process Another shell script which executes the previous one and redirects the log I check the log file with the tail -fcommand for the success message. Even if I have exit 0 in the code I cannot end the tail -fprocess. Which doesn’t let my script to finish.
How to tail a log file in Linux?
Basically, you’d define a function to be called on, say, signal 17, then put a sub-script in the background that will send that signal at some later time: Then if you reach 1200 seconds, your function is called and you can choose what to do (like signal your tail/grep combo that is watching for your pattern in order to kill it)
How to use pkill-P tail-F in bash script?
Using ‘pkill -P $$ tail’ should ensure that the right process is killed. wait_until_started() { echo Waiting until server is started regex=’Started’ tail logfile -n0 -F | while read line; do if [[ $line =~ $regex ]]; then pkill -9 -P $$ tail fi done echo Server is started }
How to start the tail of a bash script?
Start tail with –pid=$$, that way it’ll exit when the bash-process has finished. It’ll cover all cases I can think of (server hangs with no output, server exits, server starts correctly). Dont forget to start your tail before the server. tail -n0 -F logfile 2>/dev/null | while read -t 30 line
How to start and end tail in Bash?
Put a timeout on the read, tail -f logfile | read -t 30 line Start tail with –pid=$$, that way it’ll exit when the bash-process has finished. It’ll cover all cases I can think of (server hangs with no output, server exits, server starts correctly).
How does the tail command in Linux work?
Outputs the last 100 lines of the file myfile.txt. Outputs the last 10 lines of myfile.txt, and monitors myfile.txt for updates; tail then continues to output any new lines that are added to myfile.txt. The tail command follows the file forever. To stop it, press Ctrl + C.
What does tail do when you follow more than one file?
If you follow more than one file, a header will be printed to indicate which file’s data is being printed. If the file shrinks instead of grows, tail lets you know with a message. If you specify name , the file with that name is followed, regardless of its file descriptor .
Can a tail command be written without a sign?
This command can also be written as without symbolizing ‘n’ character but ‘-‘ sign is mandatory. Tail command also comes with an ‘+’ option which is not present in the head command. With this option tail command prints the data starting from specified line number of the file instead of end.
How to quit tail-F mode without using’ctrl + C’?
Answers differ based on context. To quit tail -f elegantly, you will need a trigger. Assume you are trying to monitor output of a task that will finish at some point in time – that can become your trigger. task >& filename.log & task_pid=$! tail -f filename.log & tail_pid=$! while [ 1 ] do # -0 is a special “poke” signal – “are you around?”
Is it possible to stop tailing a file?
Yes, but you will have hard time doing it – because the first command will continue to tail the file on your screen. You will have to copy paste the second line on the terminal and press ENTER. If you do it right, the tailing output on screen should stop.
Is there a way to read tail file?
The -n0won’t read anything already in the file, so you can keep appending to the logfile instead of overwriting it each time, and to standard log rotation on it. EDIT: Ok, so a rather crude ‘solution’, if you’re using tail.