Loop Script

[shanenin]

I think i have copied this script exactly as printed in my book, but it keeps failing

shane@mainbox shane $ cat scripts/loop
#!/bin/bash
x=0
while [ $x -lt 10 ]
do
   echo $x
   x=`echo "$X + 1" | bc`
done
shane@mainbox shane $ ./scripts/loop
0
(standard_in) 1: parse error
./scripts/loop: line 3: [: -lt: unary operator expected

[jcl]

Typo. 'x' is capitalized on the sixth line.

Edited April 26, 2005 by jcl

[shanenin]

thanks. I can see debugging programs being a huge undertaking. I have trouble finding them with just three lines of code

[jcl]

thanks. I can see debugging programs being a huge undertaking. I have trouble finding them with just three lines of code 

By the way, if your book doesn't mention it, that could be rewritten to use shell arithmetic expansion:

#!/bin/bash
x=0
while [ $x -lt 10 ]
do
    echo $x
    x=$(($x + 1))
done

or even:

#!/bin/bash
x=0
while [ $x -lt 10 ]
do
    echo $((x++))
done

Not that I recommend deviating from the book.

[iccaros]

what is -lt (is that like NE or !=)

while [ $x -lt 10 ]

Not that I recommend deviating from the book.

an why should you suggest a better way..

thanks

[shanenin]

what is -lt (is that like NE or !=)

it means "less then"

were you asking that?

[iccaros]

yep..

sorry with this font I thought it was (one)t and I could not figure out what that stood for..

bash is confusing to me that way.. im used to < or <= .. this lt or ne and so on alwyas cates me off guard.

thanks..

Edited April 26, 2005 by iccaros