Thread: Basic Shell Script-Very Frustrating

Im working on basic shell scripts, how do I get rid of the "-l6"

[EDIT] Added comments, the comments are added to the first script only because Im lazy and there the same in the second script [/EDIT]


//screen shots

[prompt]$ ./count4 -l6 -f1
-l6
1
2
3
4
5
6
[prompt]$ ./count4 -f1 -l6
1
2
3
4
5
6
-l6
[prompt]$

[b]//scipt file[b]

Code:

#!/bin/bash

# ./count4 -f3 -l15 print 3 to 15 to screen
if [ $1==-f* ] && [ $2==-l* ]; then
    #a becomes 3
    a=${1#-f} 
    #b becomes 15
    b=${2#-l}
    while (($a<=$b)); do
 echo $a
 a=$(($a+1))
    done
fi

#if ./count4 -l15 -f3 print 3 to 15 to screen
if [ $1==-l* ] && [ $2==-f* ]; then
    #a becomes 3
    a=${2#-f}
    #b becomes 15
    b=${1#-l}
    while (($a<=$b)); do
 echo $a
 a=$(($a+1))
    done
fi

But if I use this script file I get the output following it

Code:

#!/bin/bash

if [ $1==-f* ] && [ $2==-l* ]; then
    a=${1#-f}
    b=${2#-l}
    while (($a<=$b)); do
 echo $a
 a=$(($a+1))
    done
elif [ $1==-l* ] && [ $2==-f* ]; then
    a=${2#-f}
    b=${1#-l}
    while (($a<=$b)); do
 echo $a
 a=$(($a+1))
    done
fi

[prompt]$ ./count4 -f1 -l6
1
2
3
4
5
6
[prompt]$ ./count4 -l6 -f1
-l6
[prompt]$

starX:
This is an exercise in a text book. This is for the question above with the code.

Write a count4 script, which uses tagged arguments that concatenate the alphabetic flag and its value. Example

count4 -f5 -l7

Note there are no spaces between -f and 5

HINT: look at parameter Expansions as a way of removing the -f from -f5 to yield the number..

Salem: How do I interpret this?
[prompt]$ ./count4 -l9 -f4
set -x

# I CUT OUT THE CODE IT IS THE ABOVE ONE WITH THE ELIF STATEMENT
# I DON'T REALLY UNDERSTAND MUCH OF THIS
+ '[' '-l9==-f*' ']'
+ '[' '-f4==-l*' ']'
+ a=-l9
+ b=-f4
+ (( -l9<=-f4 ))
+ echo -l9
-l9
+ a=1
+ (( 1<=-f4 ))
[prompt]$