Using an input variable in a 'For Loop' in Bash

Question

I am trying to use the #REPLY input variable in the following for loop code below;

If I use syntax such as for i in {60..0} then it works fine however; trying the input variable from the read statement "for i in {$REPLY..0}" it fails. It appears that the read does not recognize the input as an integer value; can someone assist please?, thank you.

#!/bin/bash
clear
tput cup 5
read -p "What is the number of seconds? "
echo "Started:" $(date)
echo " "
echo " "
echo "Countdown Timer"
echo " "

for i in {$REPLY..0}
do
  tput cup 10 $1
  printf '%dh:%dm:%ds\n' $(($i/3600)) $(($i%3600/60)) $(($i%60))
  tput civis
  sleep 1
done
tput cnorm
echo " "
echo "Finished:" $(date)

Does this answer your question? How do I iterate over a range of numbers defined by variables in Bash? — Shawn
– Shawn, Commented May 25, 2020 at 23:40

Gilles Quénot · Accepted Answer · 2020-05-25 23:49:47Z

2

Yes, you can't use a variable in brace expansion. So, the solution is simple bash arithmetic form loop :

for ((i=REPLY; i>=0; i--)); do
    [...]

^{...and please, no responses with the evil eval, thanks}

edited May 25, 2020 at 23:49

answered May 25, 2020 at 23:41

Gilles Quénot

188k43 gold badges232 silver badges229 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

joe28a Over a year ago

That worked, thank you very much for your great assistance.

Collectives™ on Stack Overflow

Using an input variable in a 'For Loop' in Bash

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related