Is there a way to get the min, max, median, and average of a list of numbers in a single command?

With GNU datamash:

$ printf '%s\n' 1 2 4 | datamash max 1 min 1 mean 1 median 1
4   1   2.3333333333333 2

You can use the R programming language.

Here is a quick and dirty R script:

#! /usr/bin/env Rscript
d<-scan("stdin", quiet=TRUE)
cat(min(d), max(d), median(d), mean(d), sep="\n")

Note the "stdin" in scan which is a special filename to read from standard input (that means from pipes or redirections).

Now you can redirect your data over stdin to the R script:

$ cat datafile
1
2
4
$ ./mmmm.r < datafile
1
4
2
2.333333

Also works for floating points:

$ cat datafile2
1.1
2.2
4.4
$ ./mmmm.r < datafile2
1.1
4.4
2.2
2.566667

If you don't want to write an R script file you can invoke a true one-liner (with linebreak only for readability) in the command line using Rscript:

$ Rscript -e 'd<-scan("stdin", quiet=TRUE)' \
          -e 'cat(min(d), max(d), median(d), mean(d), sep="\n")' < datafile
1
4
2
2.333333

Read the fine R manuals at http://cran.r-project.org/manuals.html.

Unfortunately the full reference is only available in PDF. Another way to read the reference is by typing ?topicname in the prompt of an interactive R session.

---

For completeness: there is an R command which outputs all the values you want and more. Unfortunately in a human friendly format which is hard to parse programmatically.

> summary(c(1,2,4))
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
  1.000   1.500   2.000   2.333   3.000   4.000 

I actually keep a little awk program around to give the sum, data count, minimum datum, maximum datum, mean and median of a single column of numeric data (including negative numbers):

#!/bin/sh
sort -n | awk '
  BEGIN {
    c = 0;
    sum = 0;
  }
  $1 ~ /^(\-)?[0-9]*(\.[0-9]*)?$/ {
    a[c++] = $1;
    sum += $1;
  }
  END {
    ave = sum / c;
    if( (c % 2) == 1 ) {
      median = a[ int(c/2) ];
    } else {
      median = ( a[c/2] + a[c/2-1] ) / 2;
    }
    OFS="\t";
    print sum, c, ave, median, a[0], a[c-1];
  }
'

The above script reads from stdin, and prints tab-separated columns of output on a single line.