On Thu, Dec 12, 2013 at 10:33:32PM +1100, Allan Duncan wrote:
I have a rc.local script that runs fine in csh, but I'd like to change it to sh, but I've had no success at it.
#! /usr/bin/tcsh if `ping -w 1 -c 1 -n 192.168.1.3 | grep -o "1 packets"` == "1 packets" mount /nfs/bulk2
the simplest conversion to sh (with some fixes*) would be something like: #!/bin/sh if $(ping -w 1 -c 1 -n 192.168.1.3 | grep -q "1 packets") ; then mount /nfs/bulk2 fi or as a one-liner: #!/bin/sh ping -w 1 -c 1 -n 192.168.1.3 | grep -q "1 packets" && mount /nfs/bulk2 * fixes: 1. backticks are pretty much deprecated. use $(...) instead - it's clearer/more readable, avoids most shell quoting/escaping problems, and can be nested. 2. there's no need to check grep's *output* (in fact that seems redundant because the reason you're using grep is to check ping's output). grep exits with 0 on found, 1 for not found, and 2 on error. so you just need to suppress grep's normal stdout (-q does that) and check the exit code.
While we are at it, is there a more elegant way of mounting the remote partition only if that machine is on?
there's lots of ways to make it more complicated (some good, like adding error checking and perhaps multiple retries before giving up), but the above is about as simple as it gets. what do you mean by "elegant"? craig -- craig sanders <cas@taz.net.au>