07-02-2007
Backticks within backticks?
Hi, I'm trying to do something like this: range= `expr `date '+%m'` - 1` and it does not work. How can I tell it to evaluate an expression within another expression evaluation? I was at first worried that `date '+%m'` would return a string but apparently expr does the math okay normally, so the problem is how to get it to evaluate an inner set of backticks within the outer set of backticks. Thanks.
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LEARN ABOUT OPENSOLARIS
let
let(1) User Commands let(1)
NAME
let - shell built-in function to evaluate one or more arithmetic expressions
SYNOPSIS
ksh
let arg...
ksh93
let [expr...]
DESCRIPTION
ksh
Each arg is a separate arithmetic expression to be evaluated.
ksh93
let evaluates each expr in the current shell environment as an arithmetic expression using ANSI C syntax. Variables names are shell vari-
ables and they are recursively evaluated as arithmetic expressions to get numerical values. let has been made obsolete by the ((...)) syn-
tax of ksh93(1) which does not require quoting of the operators to pass them as command arguments.
EXIT STATUS
ksh
ksh returns the following exit values:
0 The value of the last expression is non-zero.
1 The value of the last expression is zero.
ksh93
ksh93 returns the following exit values:
0 The last expr evaluates to a non-zero value.
>0 The last expr evaluates to 0 or an error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO
ksh(1), ksh93(1), set(1), typeset(1), attributes(5)
SunOS 5.11 2 Nov 2007 let(1)