GNU Info

(gawk.info)V7/SVR3.1

---

Next: SVR4 Prev: Language History Up: Language History

---

Enter node , (file) or (file)node

Major Changes Between V7 and SVR3.1
===================================

   The `awk' language evolved considerably between the release of
Version 7 Unix (1978) and the new version that was first made generally
available in System V Release 3.1 (1987).  This minor node summarizes
the changes, with cross-references to further details:

   * The requirement for `;' to separate rules on a line (Note: `awk'
     Statements Versus Lines.).

   * User-defined functions and the `return' statement (Note:
     User-Defined Functions.).

   * The `delete' statement (Note: The `delete' Statement.).

   * The `do'-`while' statement (Note: The `do'-`while' Statement.
).

   * The built-in functions `atan2', `cos', `sin', `rand', and `srand'
     (Note: Numeric Functions).

   * The built-in functions `gsub', `sub', and `match' (Note: String
     Manipulation Functions.).

   * The built-in functions `close' and `system' (Note: Input/Output
     Functions.).

   * The `ARGC', `ARGV', `FNR', `RLENGTH', `RSTART', and `SUBSEP'
     built-in variables (Note: Built-in Variables).

   * The conditional expression using the ternary operator `?:' (Note:
     Conditional Expressions.).

   * The exponentiation operator `^' (*note Arithmetic Operators:
     Arithmetic Ops.) and its assignment operator form `^=' (Note:
     Assignment Expressions.).

   * C-compatible operator precedence, which breaks some old `awk'
     programs (*note Operator Precedence (How Operators Nest):
     Precedence.).

   * Regexps as the value of `FS' (Note: Specifying How Fields Are
     Separated.) and as the third argument to the
     `split' function (Note: String Manipulation Functions.
).

   * Dynamic regexps as operands of the `~' and `!~' operators (Note:
     How to Use Regular Expressions.).

   * The escape sequences `\b', `\f', and `\r' (Note: Escape
     Sequences).  (Some vendors have updated their old versions of
     `awk' to recognize `\b', `\f', and `\r', but this is not something
     you can rely on.)

   * Redirection of input for the `getline' function (Note: Explicit
     Input with `getline'.).

   * Multiple `BEGIN' and `END' rules (Note: The `BEGIN' and `END'
     Special Patterns.).

   * Multidimensional arrays (*note Multidimensional Arrays:
     Multi-dimensional.).