Command to display first few and last few lines of a file
I have a file with many rows, and each row has a timestamp at the starting, like
logs
monitor files (à la tail -f) in an entire directory (even new ones)
I normally watch many logs in a directory doing tail -f directory/*.
The problem is that a new log is created after that, it will not show in the screen (because * was expanded already).
Best way to follow a log and execute a command when some text appears in the log
I have a server log that outputs a specific line of text into its log file when the server is up. I want to execute a command once the server is up, and hence do something like the following:
How to see full log from systemctl status service?
I check service status with systemctl status service-name.
how to properly log the output of a console program that frequently updates “parts” of the screen, resulting in a messy log file?
I have some Java executable (jar) that is run my some shell script from a cron job once every night. That executable does not print log statements “as usual” just by printing them out in a sequential manner like line after line (print after print), but while it processes its data its printing a single line with status data and then “overwrite” or “update” just that single line over and over again, until its done with this part of processing.
Log every invocation of every SUID program?
I would like to have a log file that contains an entry for every time a user runs any suid program, containing the user name, the program and any command line arguments passed to it. Is there a standard way to achieve this on Linux?
Is there an equivalent of GNU Screen’s “log” command in tmux?
I make heavy use of screen’s “log” command to log the output of a session to a file, when I am making changes in a given environment. I searched through tmux’s man page, but couldn’t find an equivalent. Is anyone aware of a similar feature in tmux, or do I have to write my own wrapper scripts to do this?
recovering deleted file held open by apache?
Suppose an apache log file gets deleted but it’s held open by apache; then this is what I am doing:
How do I append/prepend a timestamp to grep output?
I am running a small linux server at home, and I am writing a script to log the temperature of the CPU cores every 5 seconds, but I need timestamps for it to be useful. So far I have something that saves the output of the sensors command into a file, and I have a command that prints the date and time. I just need to figure out how to combine those two.
Output of the “last” command
Can anybody explain me what is the meaning of the last column of the output of the last command? I’m particularly interested in its meaning with respect to the reboot pseudo-user.