1 2ed is an 8-bit-clean, POSIX-compliant line editor. It should work with 3any regular expression package that conforms to the POSIX interface 4standard, such as GNU regex(3). 5 6If reliable signals are supported (e.g., POSIX sigaction(2)), it should 7compile with little trouble. Otherwise, the macros SPL1() and SPL0() 8should be redefined to disable interrupts. 9 10The following compiler directives are recognized: 11NO_REALLOC_NULL - if realloc(3) does not accept a NULL pointer 12BACKWARDS - for backwards compatibility 13NEED_INSQUE - if insque(3) is missing 14 15The file `POSIX' describes extensions to and deviations from the POSIX 16standard. 17 18The ./test directory contains regression tests for ed. The README 19file in that directory explains how to run these. 20 21For a description of the ed algorithm, see Kernighan and Plauger's book 22"Software Tools in Pascal," Addison-Wesley, 1981. 23