[ILUG] grep or awk

[Aidan Kehoe]

 Ar an 10u la de mi 9, scriobh Chris Higgins :

 > We're talking about the contents of the wtmp/utmp files, as interpreted by
 > the command 'who'
 > 
 > If you upgrade your version of who, and the formatting changes slightly,
 > you run the risk of breaking your scripts (in strange and wonderful ways).

Anyone going to change who to do that is going to have to be both
brave & a fan of needless incompatibility. Oh, wait, this is linux. 

5:11PM ~ > uname
OpenBSD
5:13PM ~ > who -m
kehoea ttyp0    Sep 10 16:39  (my.host.name)
5:13PM ~ > 

5:14PM ~ > uname
OSF1
5:14PM ~ > who -m
kehoea      pts/8       Sep 10 16:39            (my.host.name)
5:14PM ~ > 

$ uname 
SunOS
$ who -m
kehoea     pts/1        Sep 10 17:16    (my.host.name)
$ 

$ uname 
Linux
$ who -m
pc734!kehoea   pts/6    Sep 10 17:14 (my.host.name)
$ 

 > Would it not make more sense to query the files directly so that 
 > you can be sure that the information is more reliable than grep'ing
 > from 'who'

getutent(3) and setutent(3) are less portable than who(1), believe it
or not. 

-- 
`... when the elephant man broke strong men's necks, when he'd had too 
many Powers, ...'