shell programming Syntax Error unexpected word, `$ '\ r''

I am using cygwin for shell programming and this is my first program and i can't understand the error mentioned in the title at line 4 in for loop.here is the code

ski=0
wski=1
rwski=950435
for (( i = 1; i < 77; i++ ))
do  
    if [ $i -lt 45] ; then
        dd if=3d.jpg ibs开发者_C百科=1024 count=1 skip=$ski of=myimage.dd obs=1024 seek=$wski conv=notrunc  
            expr $ski = $i
        expr $wski = $wski + $i
    else
        expr $rwski = $rwski - $i
        expr $ski = $i
        dd if=3d.jpg ibs=1024 count=1 skip=$ski of=myimage.dd obs=1024 seek=$rwski conv=notrunc
    fi
done

can someone please help me to correct this.

regards,

w

add a space after 45, ] is an argument for the function [.

but your problem is probably mixed dos/unix line endings, fix it with a proper editor or use dos2unix.