GREP -- Find Regular Expressions in Files
Revision History

GREP is a filter that searches input files, or the standard input, for lines that contain matches for one or more patterns called regular expressions and displays those matching lines.

This document is the complete revision history, starting with the most recent changes. To use GREP, please see the user guide.

v5.1, 2000-05-31:

• fix a bug: a redundant *-expression preceding $ at the end of a regular expression should have matched the end of line, but did not. Example: ab*$ would match ab, abb, abbb, etc. at end of line; but it did not match an a at end of line, as it should have.

v5.0, 2000-05-07:

• Add the /R option to read and display files in binary mode
• Add the /W option to set the line width (formerly fixed at 255 characters), and warn the user if longer lines were found
• Add the /Z option to reset all options
• Disallow out-of-order character ranges like z-a; previously they were silently treated like the three characters "z", "-", "a"
• Add new return values 2 and 252-254
• Expand the treatment of regular expressions in the help message
• Send the help message to stdout instead of stderr as previously
• Don't display the help screens when the user types grep with no options or regular expression; instead, suggest using grep /? |more
• In debug mode, add more trace message for opening input files
• When displaying a regular expression in debug mode, use a numeric to show number of members in a character class
• Fix bug in 4.5: if you used wildcards with drive but no directory, e.g. d:*, the drive was ignored

• Change file name to GREPUSER.HTM from GREP.HTM.
• Add an alphabetical index of options
• Add note about using double quotes around filenames that contain spaces.

v4.5, 1999-09-25 (general release):
v4.4, 1999-09-18 (limited release):

• Add the /S option for searching subdirectories (4.4)
• Add the /A option for searching hidden and system files (4.4)
• Add a section to the user guide to describe input files and redirection (4.4)
• Fix a bug: on the command line, regular expressions like [\244-\246\248-\255], with adjacent escaped 8-bit character ranges, were not expanded correctly (4.5)
• Systematize the debugging output somewhat, in the course of fixing the preceding bug (4.5)
• Fix a bug: on the command line, \e in regular expressions was expanded to Control-W (octal 27) instead of Escape (decimal 27) (4.5)
• Clarify and expand "Special rules for the command line" section of the user guide, clarify the descriptions of the /D and /I options, and add quite a few internal hyperlinks (4.5)

v4.3, 1999-08-04:

• Update contact information (new physical address and URL)
• Simplify registration options
• Add site license pricing

v4.2, 1999-02-20:

• Allow 8-bit characters in regular expressions
• Allow multiple regular expressions to be typed in directly, with the /F- option
• Fix a bug: with /I, character classes entered in lower case were expanded incorrectly

v4.1, 1999-01-22:

• Add the /U option (UNIX-style output) and the /Q option (quiet). Distinguish between option errors in the environment variable and on the command line
• Make all output options toggles (except /P); diagnose conflicts only after the last option has been scanned
• Take an optional output file name with /D (debug), which is no longer a toggle
• Default /P (show context lines) to 2,2 if user specifies /P without numbers
• Honor the special escape sequences only on the command line, since they're not needed when entering regular expressions in a file
• Rewrite and greatly expand the user guide. Use HTML instead of MS Word for Windows

v4.0, 1998-11-19:

• Package the existing version 4.0 for shareware release: revise documents without changing the software

v4.0, 1998-05:

• Add the /F option (multiple regular expressions in a file)
• Build a 32-bit version (to accept long filenames) along with the 16-bit version, using a single set of source files

v3.4, 1998-03:

• With the /P option, remove the < > widgets around the line numbers of the context lines, so that the lines that actually match are more easily seen

v3.3, 1998-02:

• Add the /L option
• Accept options from an environment variable
• In the output, show the file path as specified on the command line, not just the filename
• Prefix program messages with "grep:" or "grep/debug:"
• Add warning messages for incompatible or redundant sets of options
• Diagnose a regular expression containing empty brackets [] as a user error, not an internal error
• Remove the /S option (search subdirectories), because GREP's code now uses the C run-time library to interpret file specs on the command line
• Fix a bug: inside [...] in regular expressions, the backslash was swallowing an extra character

v3.2, 1997-06:

• Add the /0 and /1 options to control exit status
• /D now shows the number of matches in each file, total matches, and exit status

v3.1, 1997-01:

• Allow numeric escapes like \0x9A, \045, and \211 in the regular expression

v3.0, 1996-12:

• Add the /P option (show context lines around the actual matches)
• Display the values of all options when /D is on the command line

v2.4, 1990-04:

• Add + in regular expressions (match one or more occurrences)
• Allow options both before and after the regular expression
• Add the /S option (search subdirectories)

v2.3, 1990-03:

• Reverse the meaning of the /B option: now the default is to show only the names of matching files
• Suppress "matched 0 lines" when /C (count matches) is specified and /B is not
• Fix a bug: [...] character classes containing the range character - weren't always expanded correctly

v2.2, 1990-01:

• Add the /B option (show only the names of files that contain matches)

v2.1, 1989-12:

• Make the /D option show the input pattern as well as the decoded version
• Fix a bug: character classes [...] weren't working with the /I option

v2.0, 1989-07:

• Complete rewrite
• Add the /I option (ignore case)
• In the regular expression, add \e (escape) and \q (equal sign)

v1.0, 1986-04:

• initial version: Though all code was developed independently, I got some ideas from PC Tech Journal, May 1996, pages 191-199.