http://www.comptechdoc.org/os/linux/programming/linux_pgsignals.html
https://bash.cyberciti.biz/guide/Sending_signal_to_Processes
http://www.howtogeek.com/107217/how-to-manage-processes-from-the-linux-terminal-10-commands-you-need-to-know/
http://serverfault.com/questions/41959/how-to-send-jobs-to-background-without-stopping-them
http://stackoverflow.com/questions/625409/how-do-i-put-an-already-running-process-under-nohup
https://wiki.itcollege.ee/index.php/Cowsay
https://wiki.itcollege.ee/index.php/J%C3%B5udluse_j%C3%A4lgimine_ja_probleemilahendus_k%C3%A4surea_utiliitide_abil
http://serverfault.com/questions/41959/how-to-send-jobs-to-background-without-stopping-them
https://linuxjourney.com/lesson/job-control
https://linuxjourney.com/lesson/stderr-standard-error-redirect
http://www.computerhope.com/unix/ujobs.htm - jobs
http://unix.stackexchange.com/questions/87745/what-does-lc-all-c-do
http://stackoverflow.com/questions/2499794/how-can-i-fix-a-locale-warning-from-perl
http://askubuntu.com/questions/162391/how-do-i-fix-my-locale-issue
http://unix.stackexchange.com/questions/181433/can-signal-be-ignored-lost
https://major.io/2010/03/18/sigterm-vs-sigkill/

send capacious outputs https://help.ubuntu.com/community/Pastebinit


process management: top, htop, ps, atop
graphically: xkill (run from terminal, to cancel CTRL+C); System Monitor

in top you can use h for help

to install htop:
sudo apt update && sudo apt install htop && sudo apt-get clean

see signals: kill -l
check signal number meaning: kill -l <number>, N: kill -l 15

close process:
by PID: kill <number>
by name: killall <program name>

send kill signal to exact process by number
kill 14155

run top in background.
top&

send the list of working processes to file ps.txt
ps > ps.txt

send working jobs list to file jobs.txt
jobs -r > jobs.txt

Run text editor nano and put it to background
(is connected with exact terminal session)
nano

another terminal window check whether nano is working: ps -e | grep nano
CTRL+Z (suspend job and put background)

jobs (check whether jobs are in background and suspended)
bring back: fg 1 	(first job from list), depending on Linux distro: fg %1

Close job with signal TERM
killall -s TERM nano
killall -15 nano

Run command cowsay or /usr/games/cowsay (if games is not in PATH).
Input for cowsay take from /etc/issue and output redirect to file /var/tmp/say.txt
cat /etc/issue | LC_ALL=C cowsay > /var/tmp/say.txt

Run cowsay and take input from file /var/tmp/say.txt and redirect output to program less input
cat  /var/tmp/say.txt | LC_ALL=C cowsay | less

filter only user student processes:
top -> u, student, enter
ps -u student

Questions
---------
What's the difference between KILL and TERM signal?
Why it is not good idea to close some services (e.g. database) with KILL signal?
What happens with process, that receives signal what it will not handle? (see: man 2 signal)
Explain what will be held in environment variable PATH?

# # #

Monitor network traffic
iftop
iptraf-ng

some used commands
which
file
less
killall -l (list of signals)
man 7 signal (overview of signals), see also man -f signal