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Full Discussion: how to use expr
Operating Systems Linux Red Hat how to use expr Post 302273714 by jim mcnamara on Monday 5th of January 2009 02:52:13 PM
Old 01-05-2009
escape the * it is a shell metacharacter
Code:
a=$( expr 13 \* 3)
# or
a=`expr 13 \* 3`

This User Gave Thanks to jim mcnamara For This Post:
 

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TEST(1) 						      General Commands Manual							   TEST(1)

NAME
test, [ - test for a condition SYNOPSIS
test expr [ expr ] OPTIONS
(none) EXAMPLES
test -r file # See if file is readable DESCRIPTION
Test checks to see if files exist, are readable, etc. and returns an exit status of zero if true and nonzero if false. The legal operators are -r file true if the file is readable -w file true if the file is writable -x file true if the file is executable -f file true if the file is not a directory -d file true if the file is a directory -s file true if the file exists and has a size > 0 -t fd true if file descriptor fd (default 1) is a terminal -z s true if the string s has zero length -n s true if the string s has nonzero length s1 = s2 true if the strings s1 and s2 are identical s1 != s2 true if the strings s1 and s2 are different m -eq m true if the integers m and n are numerically equal The operators -gt, -ge, -ne, -le, and -lt may be used as well. These operands may be combined with -a (Boolean and), -o (Boolean or), ! (negation). The priority of -a is higher than that of -o. Parentheses are permitted, but must be escaped to keep the shell from trying to interpret them. SEE ALSO
expr(1), sh(1). TEST(1)
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