Linux in a Nutshell, 6th Edition

Name

for

Synopsis

for ((init; cond; incr))
do
 commandsdone

Arithmetic for loop, similar to C’s. Evaluate init. While cond is true, execute the body of the loop. Evaluate incr before retesting cond. Any one of the expressions may be omitted; a missing cond is treated as being true.

Example

Search for a phrase in each odd chapter:

for ((x=1; x <= 20; x += 2))
do
        grep $1 chap$x
done