Shell Programming and Scripting

#! /bin/bash 

count_up () 
{
  echo "Couting UP"
  n=0 
  until [[ $n -gt $1 ]]
  do
    printf "$n \n" 
    n=$(( $n + 1 )) 
  done 
}

count_down () 
{
  echo "Couting DOWN"
  n=$1
  while [[ $n -gt 0 ]]
  do
    printf "$n \n" 
    n=$(( $n - 1 )) 
  done 
} 

count_up $1
count_down $1

man seq

# seq 3 10
3
4
5
6
7
8
9
10

# cat tst
#!/usr/bin/bash
start=0
echo "start=$start"

count(){
case $1 in
    -u) let start+=$2;echo "+$2";;
    -d) let start-=$2;echo "-$2";;
    *) echo "Error : first arg should be [-u|-d]
esac
echo "start=$start"
}

count -u 5
count -d 10
count -u 3
count -u 7
count -u 40
count -d 17

# bash tst
start=0
+5
start=5
-10
start=-5
+3
start=-2
+7
start=5
+40
start=45
-17
start=28

seq 0 10
seq 5 10
seq 1 100

# cat ./lab5-4sh
#!/usr/bin/ksh
[[ $# -ne 2 ]] && echo "error 2 args required" && exit 1
[[ $1 -gt $2 ]] && ( min=$2 ; max=$1 ) || ( min=$1 ; max=$2 )
seq $min $max | xargs
seq $min $max | tail -r | xargs

seq 0 10
seq 5 10
seq 1 100

" #! /bin/bash 

count_up () 
{
  echo "Couting UP"
  n=0 
  until [[ $n -gt $1 ]]
  do
    printf "$n \n" 
    n=$(( $n + 1 )) 
  done 
}


count_down () 
{
  echo "Couting DOWN"
  n=$1
  while [[ $n -gt 0 ]]
  do
    printf "$n \n" 
    n=$(( $n - 1 )) 
  done 
} 

count_up $1
count_down $

seq 1 10 
seq 5 10 
seq 1 100 "

bash lab5-4.sh 1 10
Couting UP
0 
1 
Couting DOWN
lab5-4.sh: line 19: [[: $: syntax error: operand expected (error token is "$")
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5
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1
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...
...
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100