|
|
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
If `in words' is not present, the for command executes the commands once for each positional parameter that is set, as if `in "$@"' had been specified (see section Special Parameters). The return status is the exit status of the last command that executes. If there are no items in the expansion of words, no commands are executed, and the return status is zero. An alternate form of the for command is also supported:
for (( expr1 ; expr2 ; expr3 )) ; do commands ; done
First, the arithmetic expression expr1 is evaluated according to the rules described below . 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.
Example
#! /bin/bash
# List of manufacturers
for manufacturer in Apple Sony Panasonic "Hewlett Packard" Nokia
do
echo "Manufacturer is:" $manufacturer
done # The above could also be written as a single line... for manufacturer in Apple Sony Panasonic "Hewlett Packard" Nokia; do echo "Manufacturer is:" $manufacturer;done
"In expanding the field of knowledge, we but increase the horizon of ignorance" - Henry Miller
Related OS X commands:
break - Exit from a loop
foreach - Expand words, and execute commands
repeat - Execute a command multiple times
while - Execute commands
continue - Resume the next iteration of a while or foreach loop
Equivalent Windows NT commands:
FOR - Conditionally perform a command several times
IF - Conditionally perform a command
