How can I draw a simple histogram with three variables?

Question

I am new to unix and shell. I want to know how to draw a simple histogram with three variables which will be read from a file. The variables are random numbers that range from 1 to 100 and they will go to the Y scale and the X scale will be the time stamp of 10 minute.

Answer 1

Assuming the data consists only of integers.

Edit 2:

#!/bin/bash
limit=40
xtoggle=true
pad=5
xtitle='Seconds'
footnote='5 second intervals'
ytitle='Number (1-100)'
printf '  %*s\n' "$((limit/2 + ${#ytitle}/2 + pad))" "$ytitle"

printf ' %*d' "$pad" 0
for ((i = 5; i <= limit; i += 5))
do
    printf '%5d' "$i"
done
printf '\n\n'

while read -r -a data
do

    printf -v bar '%*s' "$limit" ''
    for i in "${data[@]}"
    do
        bar=${bar:0:i}x${bar:i+1}
    done
    if $xtoggle
    then
        xc=''
        xtoggle=false
    else
        xc="${xtitle:x++:1}"
        xtoggle=true
    fi
    printf '%-*s' "$pad" "$xc"
    printf '%s\n' "$bar"
done < bardata
if $xtoggle
then
    printf '\n'
fi
for ((i = x; i <= ${#xtitle}; i++))
do
    printf '%s\n\n' "${xtitle:i:1}"
done
printf '\n%s\n' "$footnote"

With this data:

0 5 10
10 13 16
14 3 25
8 4 12
2 20 11
5 17 19
7 8 7
14 19 30
27 22 18
11 19 23
3 33 13
8 5 1
36 18 12

This is the output:

                    Number (1-100)
     0    5   10   15   20   25   30   35   40

     x    x    x
S              x  x  x
        x          x          x
e        x   x   x
       x        x        x
c         x           x x
            xx
o                  x    x          x
                       x   x    x
n               x       x   x
        x         x                   x
d     x   x  x
                 x     x                 x
s




5 second intervals

Previous Edit:

while read -r -a data
do

    for i in "${data[@]}"
    do
        printf -v bar '%*s' "$i" ''

        bar=${bar// /*}

        printf '%s\n' "$bar"
    done
    printf '\n'
done < inputfile

For this data:

10 12 13
4 5 6
8 4 7

This is the output:

**********
************
*************

****
*****
******

********
****
*******

Original Answer (None of the indirection trickery below is necessary. ):

while read -r -a data
do

    for i in "${!data[@]}"
    do
        printf -v "bar$i" '%*s' "${data[i]}" ''

        temp=bar$i
        declare "bar$i"=${!temp// /*}

        printf '%s\n' "${!temp}"
    done
    printf '\n'
done < inputfile