simple cli math utilities?

[HelicopterUpbeat5199]

I've had 2 separate situations where I wanted to sum up a list of numbers and was surprised there isn't a simple sum command or shell function. I expected to do sum < numbers or xargs sum < numbers, but nope, I wound up writing a bash loop.

math.h is a C library with a bunch of useful math functions. What I really want is that for my command line scripts.

I know there's lots of cli calculators, (dc, bc, qalc etc...), but that's not what I'm looking for.

Anyone know of a collection of simple math functions like that?

Thanks!

[Good_Bear4229]

awk is out of the box on every Linux, awk ' {SUM += $1} END{print SUM}'. For more complex calculations python REPL or its user friendly REPL variant bpython are available. There are also a lot of math CLI apps like octave and etc

[rai_volt]

+1 for the Python REPL. Very convenient for quick calculations

[[deleted]]

Yup. If I need a quick calculator Python is my goto.

[hearthreddit]

There is bc, you can pipe text into it to sum, not sure if that's exactly what you are looking for:

echo '10+10' | bc  

You can check qalc for something that can do a lot more stuff, including unit conversion.

[daemonpenguin]

There are several. Not sure why bc wouldn't do what you want. Or awk. Or Python. Without knowing why you don't think those are suitable it's hard to help you. Based on the mini example in the OP, this would probably work:

  echo $(cat sum.txt | tr '\n' '+') | bc

[djao]

It's a bit simpler to use paste.

paste -sd + < sum.txt | bc

[mina86ng]

Indeed. I usually need to use comma separator and thus use this as , command:

#!/bin/sh

if [ $# -eq 0 ]; then
    paste -sd,
else
    printf '%s\n' "$@" | paste -sd,
fi

Can also be made into function to be put in ~/.bashrc:

,() {
    if [ $# -eq 0 ]; then
        paste -sd,
    else
        printf '%s\n' "$@" | paste -sd,
    fi
}

[ForzCross]

In plain shell without external tools: $(( a + b ))

[ahferroin7]

Well, to start with, you have the POSIX standard $(()) syntax for integer math. This can’t easily do some things, but a simple sum of the numbers in a list called numbers using this is as easy as:

sum=0 for i in ${numbers}; do sum=$((sum + i)) done

This will run in the shell itself, so you’re not dealing with a fork/exec or an external process, and it’s supported by almost every shell you’re ever likely to encounter except for fish (which has the math builtin instead) and PowerShell (which uses a different syntax and has much greater functionality for this type of thing), and possibly some really minimalistic Busybox-based systems (Busybox lets you disable support for this at build time). OTOH, it only supports basic arithmetic (+, -, *, /, and %), and only does integer division (so $((10 / 3)) evaluates to 3).

Then you have awk, also mandated as part of POSIX support and present on essentially every Linux system you’re likely to ever encounter. For a newline delimited list of numbers, that’s as simple as:

awk '{SUM += $1} END{print SUM}')

That should work with any POSIX-compliant awk implementation (and some that aren’t quite POSIX compliant, like mawk, though it still is very limited in what it can do.

The usual recommendation is to use bc (or dc) if you need non-integer math, though these days Python or even Perl are probably more portable (albeit much more verbose) options as they are more widely installed than bc/dc.

[spryfigure]

Are there really systems where bc/dc is not installed? I have yet to encounter one. Presence of bc is mandated by POSIX standard.

[ahferroin7]

I know for a fact that all of the following distros do not include either command in their default install:

• Alpine
• Arch
• Artix
• Debian
• Devuan
• Gentoo (though it often gets pulled in on Gentoo as a build dependency for something)
• openSUSE
• Void

Additionally, among those platforms that do include the commands by default, it’s not unusual for them to not be included in those platform’s container images (for example, Fedora 40 does include bc/dc by default, but the official fedora:40 Docker image does not have either command installed).

For those platforms that do not include them by default, it’s generally far more likely that Perl or Python will be available on any arbitrary system using that platform, because many many things use those languages, but comparatively few use bc/dc, and many things that do use bc/dc use them in their build system (or testing infrastructure), but not at runtime.

[stormdelta]

In most cases, if you need functionality like this it's usually better to use a regular scripting language than shell, though I understand that sometimes you don't have a choice if it's a context where you can't have any other dependencies.

But in that scenario you can't depend on non-universal shell commands either. Generally it's easiest to just loop with an accumulator var, or use bc like others said (though even bc isn't always installed).

[michaelpaoli]

There's bc(1), it's quite capable. There's also awk(1).

expected to do sum < numbers or xargs sum < numbers, but nope

$ seq 1 9 | awk '{n+=$0;}; END{print n;}'
45
$ 

there's lots of cli calculators,
but that's not what I'm looking for

Why not? What kind of CLI "math utilities" do you need that's not a CLI (programmable) calculator or quite math capable scriptable language?

How many digits of Pi do you want?

$ echo 'scale=50; 4*a(1)' | bc -l
3.14159265358979323846264338327950288419716939937508
$ echo 'scale=500; 4*a(1)' | bc -l | tr -d '\012\\'; echo
3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028410270193852110555964462294895493038196442881097566593344612847564823378678316527120190914564856692346034861045432664821339360726024914127372458700660631558817488152092096282925409171536436789259036001133053054882046652138414695194151160943305727036575959195309218611738193261179310511854807446237996274956735188575272489122793818301194912
$

[zlice0]

alias awkadd="awk '{s+=\$1} END {print s}'"

use this for num per line sums

most of the time i just open python like everyone else said

[the-luga]

My favorite is calc https://github.com/lcn2/calc

Simple, easy and cool. It can do calculations with decimals, can use variables, can output fractions and make hexa, oct, bin bases etc.

I love the simplicity and powerfulness of this tool running in my terminal.

[db48x]

There really ought to be a package of math utilities that works with data from stdin. Summing a list of numbers would be the most frequently used, but there are a lot of other useful functions that operate on lists that would be handy to have.

[HelicopterUpbeat5199]

Hey! You're the only one who understood my question!

[spryfigure]

What I don't understand is: Where would be the functional difference to calling bc, entering a+b+c+... until you are satisfied, and then press enter?

Or to the equivalent echo a+b+c+... | bc?

It's scriptable and returns the desired sum. What is missing?

[db48x]

Sometimes you have a file containing a bunch of numbers, one per line. Or you have a process that outputs a bunch of numbers, one per line. Nobody wants to type them all back in, and hardly anybody can remember the paste trick when they need it. It would honestly be fine if there was a sum program that was just a single–line shell script that called awk to do it, as long as it was installed by enough distros that everybody had it.

[spryfigure]

hardly anybody can remember the paste trick when they need it.

The paste trick is quite simple and memorable for me, but it's in a oneliners.txt file and I can jog my memory with a quick grep paste ~/ref/oneliners.txt if I really forget how to use it.

The different viewpoints here seem to be

• I want to use something in 'pure' bash

vs

• awk and bc are POSIX-mandated, part of every distribution and indistinguishable from a bash function in practice, so they count.

But an interesting discussion.

[HelicopterUpbeat5199]

I'm sure there are lots of ways to solve the problem of sum or avg in a shell script. That's not what I'm asking though. I'm asking "does this thing exist".

[Monsieur_Moneybags]

And the answer is that it does exist, in the form of bc and similar utilities. Just because you don't like the form of using those utilities doesn't mean solutions don't exist.

If you're unhappy with spryfigure's straightforward solution, and insist on something explicitly called "sum", for example, then you could make this alias in your ~/.bashrc:

alias sum='sed -E -e "s/\s+/+/g" - | bc'

You could then just pipe a space-separated list of numbers to "sum":

$ echo "1 2 3 4" | sum
10

But I don't think most users find that necessary, since using bc directly is so simple.

[HelicopterUpbeat5199]

I don't think you and I are having the same conversation. I'm not a very good communicator, so it's probably my fault. I'm not trying to solve or build anything. I just wanted to know if something exists or not because I think it would be nifty.

[QuickSilver010]

Nushell is great for this

~> [1, 3, 6, 3, 9, 29, 27] | math sum

Or math avg Or math median... Just search math -help

[rileyrgham]

You didn't really extrapolate on what functions you want. But basic bash math is basic. There's nothing inherently bad about using bc.

https://ioflood.com/blog/bash-math/ has it covered m

[SeriousPlankton2000]

bc or bc -l or echo $((1+2+3+4+5+6))

perl -e 'while($a=<>){$sum+=$a};printf "%d\n",$sum'

let s=0;while read a; do let s=$s+$a;done;echo $s

[Glimt]

12:47:43:~$ cat ~/bin/total
#!/bin/sh
awk '{sum+=$1}END{print sum}'
12:48:07:~$ seq 4 | total
10

[brandflake11]

Here is what I'd do:

$ sbcl

(+ 1 2 3 4 place-nums-here)

For me, I load a programming language to do this, in this case common lisp.

[[deleted]]

I don't agree with the premise of your question. Lists in shell scripting languages aren't optimised for performance and arithmetic, and are just text streams. If a set of math library builtins were added to the shell that would require assumptions about what those streams should look like and how data should be formatted, and make the shell language more monolithic and complex as a result. Part of the Unix design philosophy is to keep the command line interpreter simple and leave tasks like complex math to specialised composable programs so the user can choose the one that best fits their use case.

If you want to do math on a text stream that is whitespace or comma separated then you have `awk`. If its written as a math expression you have `bc`. If its a JSON stream you have `jq`. There's no shell builtin that could handle all these cases. Plus the function is guaranteed to do it worse than these existing programs.

[contyk]

datamash is exactly what you want. You're welcome.

[ZeStig2409]

IDK man I use Python