* pathos script
@ 1993-07-28 2:15 Alan Watson
0 siblings, 0 replies; 2+ messages in thread
From: Alan Watson @ 1993-07-28 2:15 UTC (permalink / raw)
To: rc
About a year ago John Mackin posted a pathos script. The idea was that
you could use it in a front-end version of a standard command to invoke
the a command further down the path.
John noted that there was a problem if if a script got exec-ed with a
relative pathname. I think I've come up with a way to get around
this. All of those pwds can take a little while, but the additional
bullet-proofing seems worthwhile to me as it doesn't cause much of a
burden in the normal case.
I prefer to use:
exec `{ pathos $0 } $*
as it alleviates the need to protect variables. On failure, pathos
prints an error message on stderr and false on stdout, which I think is
quite a nice way to deal with that situation.
BTW, John, why did you choose the name `pathos'?
Alan.
#! /tmp/alan/bin/rc --
if ( ! ~ $#* 1 ) {
echo >[2=1] usage: pathos path
echo false
exit 1
}
thisdir = `{ dirname $1 }
thisbase = `{ basename $1 }
# shift $path past $thisdir
* = $path
if ( ~ $thisdir $* ) {
while ( ! ~ $thisdir $1 ) {
shift
}
} else {
thisdir = `{ builtin cd $thisdir ; builtin pwd }
while ( ! ~ $#* 0 && ! ~ $thisdir `{ builtin cd $1 ; builtin pwd } ) {
shift
}
if ( ~ $#* 0 ) {
echo >[1=2] pathos: unable to find $thisdir in path
echo false
exit 1
}
}
shift
# look for executable $thisbase in remainder of $path
# if whatis succeeds, it prints the path on stdout for us
while ( ! ~ $#* 0 ) {
if ( whatis $1/$thisbase >[2=] ) {
exit 0
}
shift
}
echo >[1=2] pathos: unable to find $thisbase
echo false
exit 1
# end-of-file
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: pathos script
@ 1993-07-28 13:21 Alan Watson
0 siblings, 0 replies; 2+ messages in thread
From: Alan Watson @ 1993-07-28 13:21 UTC (permalink / raw)
To: rc
Oops. That first `echo >[2=1]' should be `echo >[1=2]'.
^ permalink raw reply [flat|nested] 2+ messages in thread
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