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Annotation of coherent/a/usr/man/COHERENT/expr, revision 1.1.1.1

1.1       root        1: 
                      2: 
                      3: expr                         Command                         expr
                      4: 
                      5: 
                      6: 
                      7: 
                      8: Compute a command line expression
                      9: 
                     10: eexxpprr _a_r_g_u_m_e_n_t ...
                     11: 
                     12: The  arguments to  expr form an  expression.  expr  evaluates the
                     13: expression and  writes the result on  the standard output.  Among
                     14: other uses,  expr lets the user perform  arithmetic in shell com-
                     15: mand files.
                     16: 
                     17: Each argument is a separate token in the expression.  An argument
                     18: has a logical value `false' if it is a null string or has numeri-
                     19: cal value  zero, `true' otherwise.  Integer  arguments consist of
                     20: an optional  sign followed  by a  string of decimal  digits.  The
                     21: range  of valid  integers is  that of  signed long  integers.  No
                     22: check  is made  for  overflow or  illegal arithmetic  operations.
                     23: Floating point numbers are not supported.
                     24: 
                     25: The following list gives each expr operator and its meaning.  The
                     26: list is in  order of increasing operator precedence; operators of
                     27: the  same precedence  are  grouped together.   All operators  as-
                     28: sociate left  to right except  the unary operators  `!', `-', and
                     29: `lleenn', which associate right  to left.  The spaces shown are sig-
                     30: nificant - they separate the tokens of the expression.
                     31: 
                     32: { _e_x_p_r_1, _e_x_p_r_2, _e_x_p_r_3 }
                     33:      Return expr2  if expr1 is  logically true, and  expr3 other-
                     34:      wise.  Alternatively,  { _e_x_p_r_1 , _e_x_p_r_2 }  is equivalent to {
                     35:      _e_x_p_r_1 , _e_x_p_r_2 , 00 }.
                     36: 
                     37: _e_x_p_r_1 | _e_x_p_r_2
                     38:      Return expr1 if it is true, expr2 otherwise.
                     39: 
                     40: _e_x_p_r_1 & _e_x_p_r_2
                     41:      Return expr1 if both are true, zero otherwise.
                     42: 
                     43: _e_x_p_r_1 _r_e_l_a_t_i_o_n _e_x_p_r_2
                     44:      Where relation is one of <, <=, >, >=, ==, or !=, return one
                     45:      if the relation  is true, zero otherwise.  The comparison is
                     46:      numeric  if both  arguments can  be interpreted  as numbers,
                     47:      lexicographic  otherwise.  The  lexicographic comparison  is
                     48:      the same as strcmp (see string).
                     49: 
                     50: _e_x_p_r_1 + _e_x_p_r_2
                     51: _e_x_p_r_1 - _e_x_p_r_2
                     52:      Add or  subtract the  integer arguments.  The  expression is
                     53:      invalid if either expr is not a number.
                     54: 
                     55: _e_x_p_r_1 * _e_x_p_r_2
                     56: _e_x_p_r_1 / _e_x_p_r_2
                     57: _e_x_p_r_1 % _e_x_p_r_2
                     58:      Multiply, divide,  or take remainder of  the arguments.  The
                     59:      expression is invalid if either expr is not numeric.
                     60: 
                     61: 
                     62: 
                     63: 
                     64: COHERENT Lexicon                                           Page 1
                     65: 
                     66: 
                     67: 
                     68: 
                     69: expr                         Command                         expr
                     70: 
                     71: 
                     72: 
                     73: _e_x_p_r_1 : _e_x_p_r_2
                     74:      Match  patterns (regular  expressions).   expr2 specifies  a
                     75:      pattern in the syntax used  by ed.  It is compared to expr1,
                     76:      which may  be any string.  If the  \(...\) pattern occurs in
                     77:      the  regular expression  the matching  operator  returns the
                     78:      matched field  from the  string; if  there is more  than one
                     79:      \(...\) pattern the extracted fields are concatenated in the
                     80:      result.  Otherwise, the matching operator returns the number
                     81:      of characters matched.
                     82: 
                     83: lleenn _e_x_p_r
                     84:      Return  the length  of expr.   It  behaves like  strlen (see
                     85:      string).  len is a reserved word in expr.
                     86: 
                     87: !_e_x_p_r
                     88:      Perform logical  negation: return zero if  expr is true, one
                     89:      otherwise.
                     90: 
                     91: -_e_x_p_r
                     92:      Unary minus:  return the  negative of its  integer argument.
                     93:      If the argument is non-numeric the expression is invalid.
                     94: 
                     95: ( _e_x_p_r )
                     96:      Return the expr.  The parentheses allow grouping expressions
                     97:      in any desired way.
                     98: 
                     99: Several operators have special meanings to the shell sh, and must
                    100: be quoted to  be interpreted correctly.  The characters that must
                    101: be quoted are { } ( ) < > & | *.
                    102: 
                    103: ***** See Also *****
                    104: 
                    105: commands, ed, sh, test
                    106: 
                    107: ***** Notes *****
                    108: 
                    109: expr returns  zero if the  expression is true, one  if false, and
                    110: two if an  error occurs.  In the latter case  an error message is
                    111: also printed.
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                    129: 
                    130: COHERENT Lexicon                                           Page 2
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