#!/bin/bash
# Using "seq"

echo

for a in `seq 80`  # or   for a in $( seq 80 )
# Same as   for a in 1 2 3 4 5 ... 80   (saves much typing!).
# May also use 'jot' (if present on system).
do
  echo -n "$a "
done      # 1 2 3 4 5 ... 80
# Example of using the output of a command to generate 
# the [list] in a "for" loop.

echo; echo


COUNT=80  # Yes, 'seq' also accepts a replaceable parameter.

for a in `seq $COUNT`  # or   for a in $( seq $COUNT )
do
  echo -n "$a "
done      # 1 2 3 4 5 ... 80

echo; echo

BEGIN=75
END=80

for a in `seq $BEGIN $END`
#  Giving "seq" two arguments starts the count at the first one,
#+ and continues until it reaches the second.
do
  echo -n "$a "
done      # 75 76 77 78 79 80

echo; echo

BEGIN=45
INTERVAL=5
END=80

for a in `seq $BEGIN $INTERVAL $END`
#  Giving "seq" three arguments starts the count at the first one,
#+ uses the second for a step interval,
#+ and continues until it reaches the third.
do
  echo -n "$a "
done      # 45 50 55 60 65 70 75 80

echo; echo

exit 0