How to extract the signal name with sed

Question

How to extract the signal name with sed

/usr/bin/kill -L prints:

 1 HUP      2 INT      3 QUIT     4 ILL      5 TRAP     6 ABRT     6 IOT      7 BUS      8 FPE      9 KILL    10 USR1
11 SEGV    12 USR2    13 PIPE    14 ALRM    15 TERM    16 STKFLT  17 CHLD    17 CLD     18 CONT    19 STOP    20 TSTP
21 TTIN    22 TTOU    23 URG     24 XCPU    25 XFSZ    26 VTALRM  27 PROF    28 WINCH   29 IO      29 POLL    30 PWR
31 SYS     34 RTMIN   64 RTMAX

Now I want to be able to print "11 SEGV", "12 USR2" or "SEGV", "USR2" (both solutions will be fine) by the number of a signal – with sed.

I did it with /usr/bin/kill -L|sed -n "s/(^| )11 ([^ ]+)+/<<2>>/;s/.*<<([^>]+)>>.*/1/p" – it outputs "SEGV" for 11.

But the question is – is it possible to do it simpler, without the second substitution?

Asked By: RandomB

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Source

Answer 1

You could run

/usr/bin/kill -L | grep -o '[0-9]+ [A-Z0-9]+'

to separate the signals with newline and then easily grep with grep -w "^$NUM".

Or more easy use kill -l "$NUM" 😉

$ kill -l 11
SEGV

Answered By: pLumo