How to kill all jobs in bash?

A somewhat shorter version of xhienne's answer, but not pure-bash:

jobs -p | xargs -I{} kill -- -{}

Use this:

pids=( $(jobs -p) )
[ -n "$pids" ] && kill -- "${pids[@]/#/-}"

jobs -p prints the PID of process group leaders. By providing a negative PID to kill, we kill all the processes belonging to that process group (man 2 kill). "${pids[@]/#/-}" just negates each PID stored in array pids.

You can use pkill and pgrep to kill a list of process names.

From the man page:

pgrep looks through the currently running processes and lists the process IDs which matches the selection criteria to stdout. All the criteria have to match. For example, pgrep -u root sshd will only list the processes called sshd AND owned by root. On the other hand, pgrep -u root,daemon will list the processes owned by root OR daemon. pkill will send the specified signal (by default SIGTERM) to each process instead of listing them on stdout.

An example using pgrep, pkill,

$ pgrep -l script.sh
12406 script.sh
12425 script.sh

$ pkill $(pgrep script.sh)

$ cat signal-log
Name: ./script.sh Pid: 12406 Signal Received: SIGTERM
Name: ./script.sh Pid: 12425 Signal Received: SIGTERM