initial import of NetBSD tree

1 files changed, 105 insertions, 0 deletions

diff --git a/bin/expr/expr.1 b/bin/expr/expr.1
new file mode 100644
index 00000000000..00c05b2d786
--- /dev/null
+++ b/bin/expr/expr.1
@@ -0,0 +1,105 @@
+.\"	$NetBSD: expr.1,v 1.9 1995/04/28 23:27:13 jtc Exp $
+.\"
+.\" Written by J.T. Conklin <jtc@netbsd.org>.
+.\" Public domain.
+.\"
+.Dd July 3, 1993
+.Dt EXPR 1
+.Os
+.Sh NAME
+.Nm expr
+.Nd evaluate expression
+.Sh SYNOPSIS
+.Nm expr
+.Ar expression
+.Sh DESCRIPTION
+The
+.Nm expr
+utility evaluates 
+.Ar expression
+and writes the result on standard output.
+.Pp
+All operators are separate arguments to the
+.Nm expr
+utility.
+Characters special to the command interpreter must be escaped.
+.Pp
+Operators are listed below in order of increasing precedence.
+Operators with equal precedence are grouped within { } symbols.
+.Bl -tag -width indent
+.It Ar expr1 Li | Ar expr2
+Returns the evaluation of 
+.Ar expr1 
+if it is neither an empty string nor zero;
+otherwise, returns the evaluation of
+.Ar expr2 .
+.It Ar expr1 Li & Ar expr2
+Returns the evaluation of
+.Ar expr1
+if neither expression evaluates to an empty string or zero;
+otherwise, returns zero.
+.It Ar expr1 Li "{=, >, >=, <, <=, !=}" Ar expr2
+Returns the results of integer comparison if both arguments are integers; 
+otherwise, returns the results of string comparison using the locale-specific
+collation sequence.
+The result of each comparison is 1 if the specified relation is true,
+or 0 if the relation is false.
+.It Ar expr1 Li "{+, -}" Ar expr2
+Returns the results of addition or subtraction of integer-valued arguments.
+.It Ar expr1 Li "{*, /, %}" Ar expr2
+Returns the results of multiplication, integer division, or remainder of integer-valued arguments.
+.It Ar expr1 Li : Ar expr2
+The 
+.Dq \:
+operator matches 
+.Ar expr1 
+against 
+.Ar expr2 ,
+which must be a regular expression.  The regular expression is anchored
+to the beginning of  the string with an implicit 
+.Dq ^ .
+.Pp
+If the match succeeds and the pattern contains at least one regular
+expression subexpression 
+.Dq "\e(...\e)" , 
+the string corresponding to 
+.Dq "\e1"
+is returned;
+otherwise the matching operator returns the number of characters matched. 
+If the match fails and the pattern contains a regular expression subexpression
+the null string is returned;
+otherwise 0.
+.El
+.Pp
+Parentheses are used for grouping in the usual manner.
+.Sh EXAMPLES
+.Bl -enum
+.It 
+The following example adds one to the variable a.
+.Dl a=`expr $a + 1`
+.It
+The following example returns the filename portion of a pathname stored
+in variable a.  The // characters act to eliminate ambiguity with the
+division operator.
+.Dl expr "//$a" Li : '.*/\e(.*\e)'
+.It
+The following example returns the number of characters in variable a.
+.Dl expr $a Li : '.*'
+.El
+.Sh DIAGNOSTICS
+The
+.Nm expr 
+utility exits with one of the following values:
+.Bl -tag -width Ds -compact
+.It 0
+the expression is neither an empty string nor 0.
+.It 1
+the expression is an empty string or 0.
+.It 2
+the expression is invalid.
+.El
+.Sh STANDARDS
+The
+.Nm expr
+utility conforms to
+.St -p1003.2 .