Need help on this. I need to increment a variable by 1 but retain as 2 characters.
I am using expr to do additions:
$SERIAL can range from 01-99. After adding "1", I need the result to be 2 characters, eg: 02+1 = 03. By default expr will truncate the zero such that 02+1 will become "3" not "03"
Please help. Much appreciated.
Thanks.
Last edited by Franklin52; 01-11-2012 at 07:24 AM..
Reason: Please use code tags for code and data samples, thank you
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Discussion started by: wisecracker
2 Replies
LEARN ABOUT ULTRIX
expr
expr(1) General Commands Manual expr(1)Name
expr - evaluate expressions
Syntax
expr arg...
Description
The arguments are taken as an expression. After evaluation, the result is written on the standard output. Each token of the expression is
a separate argument.
The operators and keywords are listed below. The list is in order of increasing precedence, with equal precedence operators grouped.
expr | expr Yields the first expr if it is neither null nor 0. Otherwise yields the second expr.
expr & expr Yields the first expr if neither expr is null or 0. Otherwise yields 0.
expr relop expr The relop is one of < <= = != >= > and yields 1 if the indicated comparison is true, '0' if false. The comparison is
numeric if both expr are integers, otherwise lexicographic.
expr + expr
expr - expr
Yields addition or subtraction of the arguments.
expr * expr
expr / expr
expr % expr
Yields multiplication, division, or remainder of the arguments.
expr : expr The matching operator compares the string first argument with the regular expression second argument; regular expres-
sion syntax is the same as that of The (...) pattern symbols can be used to select a portion of the first argument.
Otherwise, the matching operator yields the number of characters matched ('0' on failure).
( expr ) parentheses for grouping.
Examples
The first example adds 1 to the Shell variable a:
a=`expr $a + 1`
The second example finds the file name part (least significant part) of the pathname stored in variable a,
expr $a : '.*/(.*)' '|' $a
Note the quoted Shell metacharacters.
Diagnostics
The command returns the following exit codes:
0 The expression is neither null nor '0'.
1 The expression is null or '0'.
2 The expression is invalid.
See Alsoed(1), sh(1), test(1)expr(1)