Node:SVR4, Next:POSIX, Previous:V7/SVR3.1, Up:Language History

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 variable (see Built-in Variables).
• Multiple -f options on the command line (see Command-Line Options).
• The -v option for assigning variables before program execution begins (see Command-Line Options).
• The -- option for terminating command-line options.
• The \a, \v, and \x escape sequences (see Escape Sequences).
• A defined return value for the srand built-in function (see Numeric Functions).
• The toupper and tolower built-in string functions for case translation (see String Manipulation Functions).
• A cleaner specification for the %c format-control letter in the printf function (see Format-Control Letters).
• The ability to dynamically pass the field width and precision ("%*.*d") in the argument list of the printf function (see Format-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/ (see Using Regular Expression Constants).
• Processing of escape sequences inside command-line variable assignments (see Assigning Variables on the Command Line).