expr.1 (5923B)

1 .\" 2 .\" Sccsid @(#)expr.1 1.16 (gritter) 2/3/05 3 .\" Parts taken from expr(1), Unix 7th edition: 4 .\" Copyright(C) Caldera International Inc. 2001-2002. All rights reserved. 5 .\" 6 .\" Redistribution and use in source and binary forms, with or without 7 .\" modification, are permitted provided that the following conditions 8 .\" are met: 9 .\" Redistributions of source code and documentation must retain the 10 .\" above copyright notice, this list of conditions and the following 11 .\" disclaimer. 12 .\" Redistributions in binary form must reproduce the above copyright 13 .\" notice, this list of conditions and the following disclaimer in the 14 .\" documentation and/or other materials provided with the distribution. 15 .\" All advertising materials mentioning features or use of this software 16 .\" must display the following acknowledgement: 17 .\" This product includes software developed or owned by Caldera 18 .\" International, Inc. 19 .\" Neither the name of Caldera International, Inc. nor the names of 20 .\" other contributors may be used to endorse or promote products 21 .\" derived from this software without specific prior written permission. 22 .\" 23 .\" USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA 24 .\" INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR 25 .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 26 .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 .\" ARE DISCLAIMED. IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE 28 .\" LIABLE FOR ANY DIRECT, INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR 29 .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 30 .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 31 .\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 32 .\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 33 .\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 34 .\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 .TH EXPR 1 "2/3/05" "Heirloom Toolchest" "User Commands" 36 .SH NAME 37 expr \- evaluate arguments as an expression 38 .SH SYNOPSIS 39 .B expr 40 .I arguments 41 \&.\|.\|. 42 .SH DESCRIPTION 43 The arguments are taken as an expression. 44 After evaluation, the result is written on the standard output. 45 Each token of the expression is a separate argument. 46 .PP 47 The operators and keywords are listed below. 48 The list is in order of increasing precedence, 49 with equal precedence operators grouped. 50 .TP 51 .I expr | expr 52 yields the first 53 .I expr 54 if it is neither null nor `0', otherwise 55 yields the second 56 .I expr. 57 .TP 58 .I expr & expr 59 yields the first 60 .I expr 61 if neither 62 .I expr 63 is null or `0', otherwise yields `0'. 64 .TP 65 .I expr relop expr 66 where 67 .I relop is one of 68 < <= = != >= >, 69 yields `1' if the indicated comparison is true, `0' if false. 70 The comparison is numeric if both 71 .I expr 72 are integers, otherwise lexicographic. 73 .TP 74 .IR expr " + " expr 75 .br 76 .IR expr " - " expr 77 .br 78 addition or subtraction of the arguments. 79 .TP 80 .IR expr " * " expr 81 .br 82 .IR expr " / " expr 83 .br 84 .IR expr " % " expr 85 .br 86 multiplication, division, or remainder of the arguments. 87 .TP 88 .IR expr " : " expr 89 The matching operator compares the string first argument 90 with the regular expression second argument. 91 Regular expression syntax is the same as that of 92 .IR ed (1); 93 .B /usr/5bin/expr 94 uses simple regular expressions, 95 .BR /usr/5bin/posix/expr , 96 .BR /usr/5bin/posix2001/expr , 97 and 98 .B /usr/5bin/s42/expr 99 use basic regular expressions. 100 The 101 \fB\\(\|.\|.\|.\|\\)\fP 102 pattern symbols can be used to select a portion of the 103 first argument. 104 Otherwise, 105 the matching operator yields the number of characters matched 106 (`0' on failure). 107 .TP 108 .RI match " expr expr" 109 Same as 110 .IR expr " : " expr . 111 .TP 112 .RI ( " expr " ) 113 parentheses for grouping. 114 .TP 115 .I string 116 Yields itself 117 unless it is part of a larger expression. 118 With 119 .BR /usr/5bin/posix/expr 120 and 121 .BR /usr/5bin/posix2001/expr , 122 all 123 .I strings 124 that form valid decimal numbers 125 are converted to the canonical form. 126 .PP 127 The following operators are supported only by 128 .B /usr/5bin/s42/expr 129 or if the 130 .B SYSV3 131 environment variable is set: 132 .TP 133 .RI length " string" 134 Returns the number of characters in 135 .IR string . 136 .TP 137 .RI substr " string index count" 138 Returns a string that consists of 139 .I count 140 characters 141 beginning at position 142 .I index 143 of 144 .I string 145 (starting at 1). 146 .TP 147 .RI index " string set" 148 Returns the index in 149 .I string 150 (starting at 1) of the first occurrence 151 of one of the characters in 152 .IR set , 153 or 0 if no character is found. 154 .SH "ENVIRONMENT VARIABLES" 155 .TP 156 .BR LANG ", " LC_ALL 157 See locale(7). 158 .TP 159 .B LC_COLLATE 160 Sets the collation sequence for string comparison, 161 and for range expressions, 162 equivalence classes, and collation symbols 163 in basic regular expressions. 164 .TP 165 .B LC_CTYPE 166 Determines the mapping of bytes to characters in regular expressions, 167 for the match, length, substr, and index operators, 168 and the availability and composition of character classes 169 in basic regular expressions. 170 .TP 171 .B SYSV3 172 Enables some additional operators as described above. 173 .SH EXAMPLES 174 .PP 175 To add 1 to the Shell variable 176 .IR a : 177 .IP 178 a=\`expr $a + 1\` 179 .PP 180 To find the filename part (least significant part) 181 of the pathname stored in variable 182 .I a, 183 which may or may not contain `/': 184 .IP 185 expr "$a" : \'.*/\e(\^.*\e)\' \'\^|\' "$a" 186 .LP 187 Note the quoted Shell metacharacters. 188 .\" Historic example, not to be deleted and useful just because of its errors 189 Also note that this example generates wrong results 190 if the result of the substitution is `0' 191 or if `$a' equals one of the 192 .I expr 193 operators. 194 Be sure that your code avoids such problems 195 and use 196 .IR basename (1) 197 if to actually cut out filename parts. 198 .SH "SEE ALSO" 199 ed(1), sh(1), test(1) 200 .SH DIAGNOSTICS 201 .I Expr 202 returns the following exit codes: 203 .PP 204 0 if the expression is neither null nor `0', 205 .br 206 1 if the expression 207 is null or `0', 208 .br 209 2 for invalid expressions. 210 .SH NOTES 211 Integers are treated as 64-bit, 2's complement numbers.