how to pipe bc-calculation into shell variable

Question

I have a calculation on a Linux shell, something like this

echo "scale=4;3*2.5" |bc

which gives me an result, now I like to pipe the result of this calculation into an Variable so that I could use it later in another command,

piping into files work, but not the piping into variables

echo "scale=4 ; 3*2.5" | bc > test.file

so in pseudo-code i'm looking to do something like this

set MYVAR=echo "scale=4 ; 3*2.5" | bc ; mycommand $MYVAR

Any ideas?

score 9 · Answer 1 · answered Apr 15 '11 at 08:15

9

You can do (in csh):

set MYVAR=`echo "scale 4;3*2.5" |bc`

or in bash:

MYVAR=$(echo "scale 4;3*2.5" |bc)

answered Apr 15 '11 at 08:15

bmk

score 2 · Answer 2 · answered Apr 15 '11 at 08:14

2

MYVAR=`echo "scale=4 ; 3*2.5" | bc`

Note that bash doesn't like non-integer values - you won't be able to do calculations with 7.5 in bash.

answered Apr 15 '11 at 08:14

Erik

Nope, can’t do that with `let`. – Sven Apr 15 '11 at 08:17
2

backticks are deprecated syntax, use `$()` instead. http://mywiki.wooledge.org/BashFAQ/082 – Alexej Magura Feb 22 '14 at 19:21

score 0 · Answer 3 · answered Apr 15 '11 at 08:14

0

 MYVAR=$(echo "scale 4;3*2.5" | bc)

answered Apr 15 '11 at 08:14

Sven

3 Answers3