pert/pert

#!/bin/bash

# help text
if [ -z "$1" ] || [[ "$1" =~ [-]*(help|h) ]]; then
    echo -e "\nA command line PERT calculator for quick estimates."
    echo -e "Comma separated task list in the form \"1,2,12 4,5,9 2,3,6\", where whitespace separates tasks.\n"
    echo -e "Usage:\n\tpert [optimistic,realistic,pessimistic]\n"
    exit 1
fi

header="\n %-12s |%11s |%10s |%12s |%9s |%7s |%9s\n"
format=" %-12s |%11s |%10s |%12s |%9s |%7s |%9s\n"

divider=------------------------------
divider=" "$divider$divider$divider
width=83

scale=2
counter=0
total_estimate=0
total_standard_deviation=0
total_variance=0
for var in "$@"; do
    
    # counter iterator
    counter=$[$counter +1]
 
    # split values
    IFS=',' read -ra ADDR <<< "$var"
    
    # optimistic value
    o=${ADDR[0]}
    
    # realistic value
    r=${ADDR[1]}
    
    # pessimistic value
    p=${ADDR[2]}
    
    # header
    if [[ $counter = 1 ]]; then
        printf "$header" "task" "optimistic" "realistic" "pessimistic" "duration" "risk" "variance"
        printf "%$width.${width}s\n" "$divider"
    fi
    
    # check values
    if [ -z "$o" ] || [ -z "$r" ] || [ -z "$p" ]; then
        #echo -e "\tbad input [$o,$r,$p]"
        printf "$format" "$counter. bad input" $o $r $p
    else
    
        # pert estimate
        pert_estimate=$(echo "scale=$scale; ($o+4*$r+$p)/6" | bc -l | sed 's/^\./0./')
        total_estimate=$(echo "scale=$scale; $total_estimate + $pert_estimate" | bc -l | sed 's/^\./0./') 
        
        # standard deviation
        standard_deviation=$(echo "scale=$scale; ($p-$o)/6" | bc -l | sed 's/^\./0./')
        total_standard_deviation=$(echo "scale=$scale; $total_standard_deviation + $standard_deviation" | bc | sed 's/^\./0./')

        # variance
        variance=$(echo "scale=$scale; $standard_deviation*$standard_deviation" | bc -l | sed 's/^\./0./')
        total_variance=$(echo "scale=$scale; $total_variance + $variance" | bc | sed 's/^\./0./')
    
        # row        
        printf "$format" "$counter. task" $o $r $p $pert_estimate $standard_deviation $variance
    fi

done

if [[ $total_estimate > 0 ]]; then

    # footer        
    printf "%$width.${width}s\n" "$divider"
    printf "$format" "summary" "-" "-" "-" $total_estimate $total_standard_deviation $total_variance
    
    echo -e "\nThree point estimate:"
    
fi

echo -e "\n"