10.0;if, revision 1.0, 88/01/21
if -- Execute a conditional statement.
usage: if condition then command_1 [else command_2...] endif
DESCRIPTION
if executes a conditional statement depending on the results of a Boolean
test. You can extend the if command over several lines if you use it
interactively or in a shell script. When you use if interactively, and
extend the command over more than one line, the shell prompts you for
each new line of the command with the $_ prompt (refer to the example
below).
ARGUMENTS
condition (required)
Specify a command or program to execute and test for
truth, or specify a variable expression or Boolean
variable to test for truth. "Truth" usually means that
the command executes successfully (without any errors),
or that the shell variable expression or Boolean is
"true". (Specifically, this argument is evaluated true if
it returns an abort-severity level of 0 (zero).)
Refer to the manual, Using Your Aegis Environment for
more information on shell variables.
command_1 (required)
Specify command or program to execute if condition
returns true.
command_2 (optional)
Specify command or program to execute if condition
returns false (that is, a severity level greater than
zero).
EXAMPLES
1.
$ if eqs a a
$_ then args "a is a"
$_ else args "Aristotle was wrong."
$_ endif
a is a
$
2.
if eqs ^2 '-c'
then pas ^1
bind ^1.bin library -b ^1
else bind ^1.bin library -b ^1
endif
Example 2 might appear in a shell script. These lines compile the
Pascal module named by the first argument ^1 if the second argument ^2
is -c. Then it binds the module with library. If the second argument
is not -c, or if there is no second argument, the command simply binds
the module.
SEE ALSO
More information is available. Type
help abtsev For information about abort-severity levels