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POSIX compliant arithmetic evaluation. = 10*2+3 Show Sample Output
3=() { echo $(($*)); } -
Same functionality without using bash functions. Show Sample Output
0alias ?=concalc
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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? () { let myresult="$*" ; echo $myresult; }That would avoid changing context (launching a new process, that's what "bc" is) and would be much faster if you are using the calculations in some loop or whatever. To ensure that, I made a quick test: I defined "?" as my function, and "x" as your function, and measured their times for a simple compound calculation:time ( for a in {0..999}; do ? "($a*$a-$a)/($a+$a+1)" > /dev/null ; done )real 0m0.767s user 0m0.624s sys 0m0.144stime ( for a in {0..999}; do x "($a*$a-$a)/($a+$a+1)" > /dev/null ; done )real 0m6.777s user 0m1.544s sys 0m4.548s Of course, it might be that you would miss some functionality for advanced calculations using the internal shell syntax instead of bc. But then again, bc (-l or not) has its limitations: you can't use it for non-integer exponentials, that is:echo "2^(1/3)" | bc -lRuntime warning (func=(main), adr=9): non-zero scale in exponent I would recommend installing the "concalc" package if you need better mathematical evaluations in shell commands:echo "2^(1/3)" | concalc1.25992104989487316?as a function name. Thanks for the example for that, even if I don't use the calculator function! :)<<< "x=1; y=2; p=3*x+2*y; p" bc -lecho $[ 1*2 + 3 ]5bc <<< 10*2+3# bash arithmeticfunction ? { echo $[$*] }# awk arithmetic (floating point result)function calc(){ awk "BEGIN{ print $* }" ;}bc -l<<<3/7echo $[2*(3+5)]16 awk for floating point and powersfunction ? { awk "BEGIN{ print $* }" ;}? '((2+1)/7)^3.5'0.0515325 concalc for full scientific functions:concalc<<<'sin(32^(1/3))'-0.0332033464121159848 bc for high precision:bc -l<<<3/7.42857142857142857142 gp for number theory: gp -qf 2.6040699049291378729513930560926568818 E574964gp -qf2.6040699049291378729513930560926568818 E574964gp -qf<<<'123456! + 0.'2.6040699049291378729513930560926568818 E574964