Question

I’m trying to run a loop that will run matlab command in the background the following way:

while [$i -lt $p] || [$i -eq $p] do
     $i>i.txt
     echo "matlab -nojvm -r readtxt_abc;pause(1);myfunc1(a,b,c);clear" |sh &
     let i=i+1
done

and I get an error of

bash:syntax error near unexpected token 'done'

if anyone have any idea what is the reason for the error pls let me know, thank u!

Answer 1

Square brackets require spaces around them since they are, in essence, commands instead of syntax elements. You also need a semicolon when you put do on the same line as while.

while [ $i -lt $p ] || [ $i -eq $p ]; do

The less-than-or-equal operator is -le instead of doing two tests.

However, this is preferred in Bash:

while ((i <= p)); do
     # $i>i.txt     # this line doesn't make any sense
     matlab -nojvm -r 'readtxt_abc;pause(1);myfunc1(a,b,c);clear' &    # there's no need to pipe this to sh
     ((i++))
done

But you can let Bash maintain your counter variable:

for ((i = 0; i <= p; i++)); do
    . . .
done

Perhaps the second line should be:

echo "$i" > "$i.txt"

but I don’t know why you’d want to do that.