Current Count vs Total Count output in a single line using Bash - bash

Question

I need an output of current count vs total count in single line. I would like to know if this could be done Via Bash using 'for' 'while' loop.
Expecting an output that should only update the count and should not display multiple lines
File Content
$ cat ~/test.rtf
hostname1
hostname2
hostname3
hostname4
#!/bin/sh
j=1
k=$(cat ~/test.rtf | wc -l)
for i in $(cat ~/test.rtf);
do
echo "Working on line ($j/$k)"
echo "$i"
#or any other command for i
j=$((j+1))
done
EX:
Working on line (2/4)
Not like,
Working on line (2/4)
Working on line (3/4)

Answer 1

Assumptions:
OP wants to generate n lines of output that overwrite each other on successive passes through the loop
in OP's sample code there are two echo calls so in this case n=2
General approaches:
issue a clear at the beginning of each pass through the loop so as to clear the current output and reposition the cursor at the 'top' of the console/window
use tput to manage movement of the cursor (and clearing/overwriting of previous output)
Sample input:
$ cat test.rtf
this is line1
then line2
and line3
and last but not least line4
real last line5
clear approach:
j=1
k=$(wc -l < test.rtf)
while read -r line
do
clear
echo "Working on line ($j/$k)"
echo "${line}"
((j++))
done < test.rtf
tput approach:
j=1
k=$(wc -l < test.rtf)
EraseToEOL=$(tput el) # grab terminal specific code for clearing from cursor to EOL
clear # optional: start with a new screen otherwise use current position in console/window for next command ...
tput sc # grab current cursor position
while read -r line
do
tput rc # go (back) to cursor position stored via 'tput sc'
echo "Working on line ($j/$k)"
echo "${line}${EraseToEOL}" # ${EraseToEOL} forces clearing rest of line, effectively erasing a previous line that may have been longer then the current line of output
((j++))
done < test.rtf
Both of these generate the same result:

Answer 2

Something along these lines:
file=~/test.rtf
nl=$(wc -l "$file")
nl=${nl%%[[:blank:]]*}
i=0
while IFS= read -r line; do
i=$((i+1))
echo "Working on line ($i/$nl)"
done < "$file"

Answer 3

Your main question is how to avoid each the counter to be written to new lines. The newlines are \n characters, which is appended by echo. You want \r, like
for ((i=0; i<10; i++)); do
printf "Counter $i\r"
sleep 1
done
echo
When you echo something from the line you are working on, you will use \n again. I will use cut as an example of processing the inputline. Use the output string in the same printf command like
j=1
k=$(cat ~/test.rtf | wc -l)
while IFS= read -r line; do
printf "Working on line (%s): %s\r" "$j/$k" $(cut -c1-10 <<< "${line}")
sleep 1
((j++))
done < ~/test.rft
The problem with the above solution is that you will see output from previous lines when your last output is shorter than the previous one. When you know the maximum length that your processing of the line will show, you can force additional spaces:
j=1
k=$(cat ~/test.rtf | wc -l)
while IFS= read -r line; do
printf "Working on line (%5.5s): %-20s\r" "$j/$k" "$(cut -c1-20 <<< "${line}")";
sleep 1
((j++))
done < ~/test.rft