File: gawk.info,  Node: SVR4,  Next: POSIX,  Prev: V7/SVR3.1,  Up: Language History

A.2 Changes Between SVR3.1 and SVR4
===================================

The System V Release 4 (1989) version of Unix 'awk' added these features
(some of which originated in 'gawk'):

   * The 'ENVIRON' array (*note Built-in Variables::)

   * Multiple '-f' options on the command line (*note Options::)

   * The '-v' option for assigning variables before program execution
     begins (*note Options::)

   * The '--' signal for terminating command-line options

   * The '\a', '\v', and '\x' escape sequences (*note Escape
     Sequences::)

   * A defined return value for the 'srand()' built-in function (*note
     Numeric Functions::)

   * The 'toupper()' and 'tolower()' built-in string functions for case
     translation (*note String Functions::)

   * A cleaner specification for the '%c' format-control letter in the
     'printf' function (*note Control Letters::)

   * The ability to dynamically pass the field width and precision
     ('"%*.*d"') in the argument list of 'printf' and 'sprintf()' (*note
     Control Letters::)

   * The use of regexp constants, such as '/foo/', as expressions, where
     they are equivalent to using the matching operator, as in '$0 ~
     /foo/' (*note Using Constant Regexps::)

   * Processing of escape sequences inside command-line variable
     assignments (*note Assignment Options::)