Using bash inline
less-than less-than eeooff bc
> k=1024
> m=k*k
> g=k*m
> g
> eeooff
1073741824
b) using the "inline" verion with three less-than symbols:
less-than less-than less-than "k=1024; m=k*k; g=k*m; g" bc
1073741824
One nice advantage of using the triple less-than version is that the command can easily be recalled
from command line history and re-executed.
PS: in this "description", I had to use the name "less-than" to represent the less-than symbol because the commandlinefu input text box seems to eat up the real less-than symbols. Odd.
$ # example 1: with the "bc" (basic calculator) command $ <<<"k=1024; m=k*k; g=k*m; g" bc 1073741824 $ # example 2: with the "at" command $ <<< "/home/mirror/cron_rsync_mandriva_updates" at now + 1 min warning: commands will be executed using (in order) a) $SHELL b) login shell c) /bin/sh job 66 at Sat Jun 20 11:33:00 2009 $ # example 3: calculating how long it takes for a signal across the Atlantic in fibre optic cable $ # reference: https://en.wikipedia.org/wiki/Speed_of_light $ # example 3, part 1: how fast does light travel in glass? $ bc <<< "scale=4; speedoflight=186282; speedoflight/1.5" # light in glass travels at c / 1.5 124188.0000 $ # example 3, part 2: how many seconds for light to cross Atlantic in glass? $ bc <<< "scale=4; ocean=3716; speedoflight=124188; ocean/speedoflight" .0299
1 Alternatives + Submit Alt
-
Don't do this:
echo word | commandUsing a bash "here strings" and "here documents" look leeter than piping echo into the command. Also prevents subshell execution. Word is also expanded as usual.12command <<< word
What do you think?
Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?
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echo "k=1024; m=k*k; g=k*m; g" | bcI think it's easier to understand, and it's more portable (works with any bourne shell, not just bash and zsh).