How to make a for loop in command line?

The syntax of a for loop from the bash manual page is

for name [ [ in [ word ... ] ] ; ] do list ; done

The semicolons may be replaced with carriage returns, as noted elsewhere in the bash manual page: "A sequence of one or more newlines may appear in a list instead of a semicolon to delimit commands."

However, the reverse is not true; you cannot arbitrarily replace newlines with semicolons. Your multiline script can be converted to a single line as long as you observe the above syntax rules and do not insert an extra semicolon after the do:

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

The semicolon after do is an error and should not be there.

The following works correctly:

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