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Use top to monitor only all processes with the same name fragment 'foo'
$ pgrep foo may return several pids for process foobar footy01 etc. like this: 11427 12576 12577 sed puts "-p " in front and we pass a list to top: $ top -p 11427 -p 12576 -p 12577

tar exclude files or directories
If you want to exclude only one file or directory you should use as --exclude=file_or_directory

Generate a 18 character password, print the password and sha512 salted hash
Generate a 18 character password from character set a-zA-Z0-9 from /dev/urandom, pipe the output to Python which prints the password on standard out and in crypt sha512 form.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

cleanup /tmp directory
Cleans all files in /tmp that have been accessed at least 2 days ago.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

find previously entered commands (requires configuring .inputrc)
[Click the "show sample output" link to see how to use this keystroke.]   Meta-p is one of my all time most used and most loved features of working at the command line. It's also one that surprisingly few people know about. To use it with bash (actually in any readline application), you'll need to add a couple lines to your .inputrc then have bash reread the .inputrc using the bind command:   $ echo '"\en": history-search-forward' >> ~/.inputrc   $ echo '"\ep": history-search-backward' >> ~/.inputrc   $ bind -f ~/.inputrc     I first learned about this feature in tcsh. When I switched over to bash about fifteen years ago, I had assumed I'd prefer ^R to search in reverse. Intuitively ^R seemed better since you could search for an argument instead of a command. I think that, like using a microkernel for the Hurd, it sounded so obviously right fifteen years ago, but that was only because the older way had benefits we hadn't known about.     I think many of you who use the command line as much as I do know that we can just be thinking about what results we want and our fingers will start typing the commands needed. I assume it's some sort of parallel processing going on with the linguistic part of the brain. Unfortunately, that parallelism doesn't seem to work (at least for me) with searching the history. I realize I can save myself typing using the history shortly after my fingers have already started "speaking". But, when I hit ^R in Bash, everything I've already typed gets ignored and I have to stop and think again about what I was doing. It's a small bump in the road but it can be annoying, especially for long-time command line users. Usually M-p is exactly what I need to save myself time and trouble.     If you use the command line a lot, please give Meta-p a try. You may be surprised how it frees your brain to process more smoothly in parallel. (Or maybe it won't. Post here and let me know either way. ☺)

using tee to echo to a system file with sudo privileges
We sometimes need to change kernel parameters by echoing the file . This needs root privilege and if we do it using sudo like this , it fails $ sudo echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor -bash: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor: Permission denied We can achieve this with the tee command by just doing sudo without logging as root user http://www.zaman4linux.in/2010/09/using-tee-to-echo-to-system-file-with.html


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