How to show the percentage progress of script execution in Unix?

Question

Suppose you run some script such as a perl or tcl. For example, $ ./script.sh; ./script.pl; source script.tcl. It takes some time to get executed and return to prompt. How to display the percentage of execution meanwhile the execution?

Below you can find an example UI. It displays the execution time taken for the script at the end.

1% Completed the exectuion of script.pl
2% Completed the exectuion of script.pl
. . . .
100% Completed the the exectuion of script.pl

Ex: Execution time for script.pl is :50 Seconds

Answer 1

The following script shows:

1. Current item (iteration) number
2. Sliding window average rate (eg. average over 10 iterations)
3. Overall average rate
4. The percentage progressed so far (if the number of irrigation is known)

The output:

317:  window: 3.76/s   overall: 3.28/s   progress: 31.7%

The test file:

set test_file
# create a test file
for i in {1..1000} ;do echo $i; done >"$1"

The script:

if="$1"             # the input file
lct=$(wc -l <"$if") # number of lines in input file
tot=${lct:-0}       # total number of itterations; If unknown, default is 0
                    #+  The total is know in this case. '$tot' is just a rough 
                    #+  example of how to suppress the progress %age output
beg=$(date +%s.%N)  # starting unix time.%N is nanoseconds (a GNU extension)
swx=10              # keep a sliding window of max 'n' itteratons (to average)
unset sw            # an array of the last '$swx' rates
for i in $(seq 1 $lct) ;do
    sw[$i]=$(date +%s.%N)  # sliding window start time
    # ================                   
      sleep .$RANDOM       #  ... process something here
    # ================
    now=$(date +%s.%N)     # current unix time
    if ((i<=swx)) ;then
        sw1=1              # first element of sliding window  
        sww=$i             # sliding window width (starts from 1)
    else
        sw1=$((i-swx+1))
        sww=$swx        
    fi
    bc=($(bc <<<"scale=2; $i/($now-$beg); $sww/($now-${sw[$sw1]})"))
    oavg=${bc[0]}                  # overall average rate
    swhz=${bc[1]}                  # sliding window rate
    ((i>swx)) && unset sw[$sw1-1]  # remove old entry from sliding window list
    ((tot==0)) && pc= || pc="progress: $(bc <<<"scale=1; x=($i*100)/$tot; if (x<1) print 0; x")%"
    msg="$i:  window: $swhz/s   overall: $oavg/s   $pc"
    printf "\r%"$((${#i}+1))"s=\r%s" "" "$msg"
done