kill command SIGKILL vs SIGTERM

Question

there was a nice write up somewhere on here about...

not using kill-9 all the time which is SIGKILL and explained the reasons for doing so, and then went on to explain an order in which one should proceed from least aggressive SIGTERM ending up eventually at SIGKILL or rebooting.

can someone post a link to that for me? i cannot find it

using kill -l to do a listing I receive as output on the terminal

this is kill dash lowecase L, and NOT dash numeral one

HUP   INT    QUIT     ILL      TRAP     ABRT     BUS      FPE      KILL   USR1
SEGV  USR2   PIPE     ALRM     TERM     STKFLT   CHLD     CONT     STOP   TSTP
TTIN  TTOU   URG      XCPU     XFSZ     VTALRM   PROF     WINCH    POLL   PWR
SYS   RTMIN  RTMIN+1  RTMIN+2  RTMIN+3  RTMAX-3  RTMAX-2  RTMAX-1  RTMAX

I spaced out the above for readability. This is from SLES 11.4 x86-64

Am I correct in assuming the order of which these signal names are printed from kill -l correspond to the number you provide the kill command, such that if I wanted the bad KILL I would do kill -9 and if I wanted the better choice of TERM that would be kill -15 ?

• Is this the only way to find out these numbers on a given system?
• Is there a better more universal way of verifying what signals are available on a given linux system {RHEL, SuSE, debian, ... some stripped down version of linux from i don't know where used on some piece of hardware}?
• If I write code, where & how should one check something system level like this before assuming a signal is: first available, and then that kill -number corresponds to a specific signal?
• is there a good source for learning about all these types of signals, and what should be expected to always be available, for a typical Linux operating sytem?