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I have a small script, which is called daily by crontab using the following command:
/homedir/MyScript &> some_log.log The problem with this method is that some_log.log is only created after MyScript finishes. I would like to flush the output of the program into the file while it's running so I could do things like
tail -f some_log.log and keep track of the progress, etc.
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with the current version of bash, modifying a script on-disk while it is running will cause bash to "try" to load the changes into memory and take these on in the running script. if your changes come after the currently executing line, the new lines will be loaded and executed.
Use the fflush Function to Flush stdout Output Stream in C As a result, there are buffers maintained by the C library for handling the input/output operations when using the stdio function calls. If the user needs to force writing to kernel buffers, it needs to flush the given stream provided by the fflush function.
There are many methods to quit the bash script, i.e., quit while writing a bash script, while execution, or at run time. One of the many known methods to exit a bash script while writing is the simple shortcut key, i.e., “Ctrl+X”. While at run time, you can exit the code using “Ctrl+Z”.
The bash wait command is a Shell command that waits for background running processes to complete and returns the exit status. Unlike the sleep command, which waits for a specified time, the wait command waits for all or specific background tasks to finish.
I found a solution to this here. Using the OP's example you basically run
stdbuf -oL /homedir/MyScript &> some_log.log and then the buffer gets flushed after each line of output. I often combine this with nohup to run long jobs on a remote machine.
stdbuf -oL nohup /homedir/MyScript &> some_log.log This way your process doesn't get cancelled when you log out.
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script -c <PROGRAM> -f OUTPUT.txt Key is -f. Quote from man script:
-f, --flush Flush output after each write. This is nice for telecooperation: one person does 'mkfifo foo; script -f foo', and another can supervise real-time what is being done using 'cat foo'. Run in background:
nohup script -c <PROGRAM> -f OUTPUT.txt If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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