Like most, I learned shell scripting by following examples. Well, unfortunately, most of the samples I learned from used the ‘seq’ binary to execute a simple for loop like so:

for i in `seq 1 10`; do
echo $i
done

I discovered why this is bad today - not all Unixes (Solaris and Darwin included) come with it. Not to mention we’re forking a process where we don’t need it. On bash, use the built-in brace expansion instead:

for i in {1..10}; do
echo $i
done

For ksh and other shells, instead of using a for, use a while loop with an incrementing counter if the integers are too numerous to list in the loop header itself.