Three scripting questions
in [UK Linux]
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From: Richard Kettlewell on 3 Mar 2010 03:06 Tom Anderson <twic(a)urchin.earth.li> writes: > Oh, that reminds me of another one that came up today. I have three > scripts, stop, prepare, and start; i need to run stop and prepare > before i can run start, but i can run stop and prepare in parallel. I > can write a master script: > > stop & > prepare > wait > start > > But the exact set of commands is fairly ad-hoc, due to changing > parameters and whatnot, so writing a script seems like overkill. Is > there a way to do this on the command line? This: > > stop &; prepare; wait; start > > Fails, apparently because the & needs to be the last thing on the > line, and a ; doesn't count as end of line. This: [...] ";" and "&" act as separators not (just) terminators. e.g.: $ sleep 1 & echo spong ; wait ; echo done [1] 93002 spong [1]+ Done sleep 1 done $ http://bit.ly/aK0vLZ -- http://www.greenend.org.uk/rjk/
From: Tom Anderson on 3 Mar 2010 16:07
On Wed, 3 Mar 2010, Richard Kettlewell wrote: > Tom Anderson <twic(a)urchin.earth.li> writes: >> Oh, that reminds me of another one that came up today. I have three >> scripts, stop, prepare, and start; i need to run stop and prepare >> before i can run start, but i can run stop and prepare in parallel. I >> can write a master script: >> >> stop & >> prepare >> wait >> start >> >> But the exact set of commands is fairly ad-hoc, due to changing >> parameters and whatnot, so writing a script seems like overkill. Is >> there a way to do this on the command line? This: >> >> stop &; prepare; wait; start >> >> Fails, apparently because the & needs to be the last thing on the >> line, and a ; doesn't count as end of line. This: > [...] > > ";" and "&" act as separators not (just) terminators. e.g.: > > $ sleep 1 & echo spong ; wait ; echo done > [1] 93002 > spong > [1]+ Done sleep 1 > done > $ Aaaaaaaaaah. Or to put it in terms of the misunderstanding i was labouring under: in the case of a single command being run in the background, & is the terminator, not the carriage return. Yes, that solves my problem entirely, thanks. tom -- alle Menschen werden Br |