for-Linux Command

for

Expand words, and execute commands once for each member in the resultant list, with name bound to the current member.

SYNTAX
      for name [in words ...]; do commands; done

for (( expr1 ; expr2 ; expr3 )) ; do commands ; done

First, the arithmetic expression expr1 is evaluated according to shell arithmetic expression rules. The arithmetic expression expr2 is then evaluated repeatedly until it evaluates to zero.

Each time expr2 evaluates to a non-zero value, commands are executed and the arithmetic expression expr3 is evaluated. If any expression is omitted, it behaves as if it evaluates to 1.

The return value is the exit status of the last command in list that is executed, or false if any of the expressions is invalid.

Positional Parameters
These are assigned from the shell's arguments when the shell is invoked, they can be reassigned using the set builtin command.
Positional parameter N may be referenced as ${N}, or as $N when N consists of a single digit. $1, $2 etc

Example

#! /bin/bash
# List of manufacturers
for m in Apple Sony Panasonic "Hewlett Packard" Nokia
do
  echo "Manufacturer is:" $m
done


# The above could also be written as a single line...
for m in Apple Sony Panasonic "Hewlett Packard" Nokia; do echo "Manufacturer is:" $m;done