GREP — Find Regular Expressions in Files

Summary: This document is the complete revision history, starting with the most recent changes. To use GREP, please see the GREP Quick Start Guide and the GREP Reference Manual.

Release 8.01, 7 Dec 2021

GREP is now hosted at BrownMath.com, not at OakRoadSystems.com. Why the switch? I own both domains and thought it would be easier to maintain one than two, so I am moving everything from OakRoadSystems.com, the smaller site, over to BrownMath.com.

In the actual program, the only change is to the logo line, which you won’t see if you use the /Q option. There are quite a few changes to the documents listed above.

Changes to the download file:

• Previously, the HTML documents were not included, and you had to go to the Web to read them. They have been restored to the ZIP file for the convenience of people who may not have a suitable Internet connection.
• The tour is now in a subdirectory in the ZIP file, which required some minor code changes. The docs are in another subdirectory.
• The GREP Quick Reference Card, formerly a Microsoft Word file, is now a PDF.

3 Feb 2019

The unregistered version of GREP was withdrawn, and the registered version was made freeware.

References to registered and unregistered versions remain in the history below, but no longer have practical effect.

Release 8.0, 5 May 2005

New features:

• The new letter /o option lets you specify output format independent of input format.

  Compatibility note: Release 8.0 changes the default output format for text lines (not paragraphs). Earlier releases simply dumped the input lines naïvely. Release 8.0 displays control characters in ^letter format and other non-printing characters in <nn> format. In most cases this is a good thing, but if you want the old behavior specify the /o1 option on the command line or in the environment variable.

• The functions that read text files were completely overhauled. Now GREP recognizes line terminators in DOS, UNIX, or Macintosh-format files; and Control-Z and NUL are treated like any other characters. This affects paragraph mode (/G2 option) and both line modes (/G0 or /G1 option). I'm grateful to Scott Brueckner for an excellent set of test cases in his Reading Text Files in C. Although I didn't use any of his C code, I did benefit greatly from his research into the issues with the standard C library.

  With the /G0 option (fixed-width text lines), earlier releases of GREP would chop the line into chunks of txwid+1 characters as specified in the /W option; release 8.0 chops the line into chunks of exactly txwid characters.

• The /P option (show context lines) was previously illegal with the /R3 option. Now, GREP32 /J /R3 /Pb,a supplies context in bytes, up to b bytes before and a bytes after. (The /J option is required.)
• When GREP prompts you to enter input files, regexes, or input lines at the keyboard, it now tells you the maximum length of input allowed.
• The exit status is now displayed with the numbers of hits and files.
• If you specify the new /3 option, then GREP will set the return value to 3 if there are warnings but no errors.
• The debug message (/D option) at the end of each file now gives you both the item count and the line or byte count.

Bugs fixed:

• Two long-standing bugs in basic regexes (unnoticed since May 2000!) were discovered and fixed: the regex .* wasn't matching an empty line, as it should; and the naked dollar sign $, which should match every line, wasn't matching any. (Extended regexes, /E2 option, were not implicated.)
• Release 7.5, if you used the /U option, /N option, /R2 option, and /P option all used together, failed to distinguish visually between records that contain matches and records displayed for context. As in previous releases, in release 8.0 a colon follows the file name only for the records that contain matches.

Other program changes:

• With the /N option in paragraph mode (/G2 option), GREP now displays the line number followed in parentheses by the paragraph number. Also with the /N option, byte numbers from free-format binary files (/R3 option) are now prefixed with B to distinguish them from line numbers.
• The /X option exclusions now apply only to input filespecs that contain wildcards. The idea is that if you explicitly specify a single file without wildcards, you must want GREP to process it. (Previously, if the environment variable contained /X*txt and you typed grep warning prog.txt on the command line, GREP would ignore the prog.txt input file because it matched the exclusion.)
• The pseudo-file NUL is now ignored. (Previously, GREP interpreted it as an interactive device.)
• When input is redirected from file or piped from another command, GREP now ignores the /R option.
• The binary buffer size (/W option) must be an even number with the /R3 or /R-1 or /R-2 option. Previously, GREP enforced this requirement by means of a fatal error. Now, GREP displays a level-1 warning, adjusts the binary width to the next even number, and continues.
• With fixed-length records (/R2 option), GREP now warns you if the last record is short, which could mean the /W option wasn't specified correctly.
• The warning "^ and $ are not recommended in a basic regex with /R3" (or /R−1 or /R−2) was eliminated because it didn't always appear when it should and often appeared where it shouldn't.
• The nag message at the beginning of the unregistered version was shortened.

Documentation changes:

• The help message (grep /?) is now much more explicit about the /0 or /1 option, and reserved modes /G3 and higher are no longer mentioned. The placement of "(default)" is now uniform.
• The interactive tour never got thoroughly tested under Windows XP because I didn't have free access to an XP system until early 2005. Caret (^) characters in regexes were a particular problem. Now the tour should work in DOS 5.0 through Windows XP.
• The GREP Manual now explains how to run GREP from the Windows desktop.
• In the GREP Manual, the terms standard input, standard output, and standard error are now defined; and uses of those terms are cross referenced to the definitions. Similarly, the GREP Manual now defines whitespace characters; and uses of the terms hits, filespec, and wildcard now link to the definitions of those terms.
• The 0README.1ST file was reorganized, and a few usage notes were added.

Release 7.52, 17 Jan 2005

The TOURKEY program (see release 7.51) was compiled with a 16-bit compiler to keep it small. It worked fine on my Windows XP Pro, but a user reported that it didn't work on his. I recompiled it with a 32-bit compiler. Also, though TOURKEY isn't intended for standalone use, I added a program identification and help message if you run it with the /? option.

In the tour itself, I simplified the regex used with GREP32 to illustrate paragraph mode .

The GREP executables and the other documentation are unchanged from release 7.5.

Release 7.51, 29 Dec 2004

Following a report that the tour didn't work in Windows XP, I investigated and found that the default installation of Windows XP doesn't have the CHOICE program, which the tour uses to get instructions from the user. I wrote a workalike, TOURKEY, which is now included with the distribution.

The executables and documentation are unchanged.

Release 7.5, 19 Dec 2004

Program changes affecting text files:

• The new /G2 option makes GREP search paragraphs rather than lines. This is very handy for text files where a match might begin on one line and end on a later line; it's also a more flexible way to show context than the /P option.
• You no longer need to preset the text width (first number in the /W option): GREP now allocates memory dynamically to take in any length of text line. (This change affects GREP16 users much more than GREP32 users, because the default line length was already very large in GREP32.) If you really want the old behavior, where GREP chops lines in the middle at the stated width, use the new /G0 option.
• Large text files should now be processed about 16% faster than before. (I benchmarked read speeds for pairs of identical 7 MB files that, to the best of my understanding, were not cached.)

Program changes in the handling of multiple regexes (/F option) with the /J2 or /J3 option:

• GREP now reports all matches in the order they occur on the input line. (Previously, within any given line or buffer GREP first reported all matches for the first regex in the /F file, then all matches for the second regex, and so on.)
• With multiple regexes, the /J2 option (display all matching parts of the line, without overlaps) was documented in release 7.4 to report overlaps of matches for different regexes but not overlaps of matches for the same regex. Now, GREP /J2 won't display a given part of the input more than once, even if it matches more than one regex.

The above two changes don't affect single regexes with the /J2 or /J3 option.

Other program changes:

• There is a new format for binary output, a change that was overwhelmingly favored in a GREP user poll. Previously, binary output was the same as text output except that non-printable characters were replaced by a hex representation in < > angle brackets. Now, binary output shows a hex dump and text representation side by side; with non-printable characters represented by dots.
• Line numbers and /C option counts can now go as high as 2³²−1, which is 4,294,967,295 (an unsigned long), after which they will silently roll over to 0. Previously, GREP16 counts went to 32,767 and GREP32 counts went to 2,147,483,647, after which they silently rolled over to negative numbers. (Thanks to Scott McEndree for the suggestion.)
• Prompts are now written to the standard error output. This affects prompts for regexes (/F- option) and files (/@- option) and lines to test (if no input files are specified). Previously they were written to the C library "console", which on some systems gets redirected along with standard output.
• In the debug output (/D option), messages about memory allocation are now headed "grep GA". Previously they were distributed among the other categories.
• Some warnings about combinations of command-line options used to be displayed before the program logo. Now the logo is displayed first.
• The unregistered version now displays a request for feedback at the end of execution. Also, about one time in a hundred it requires a keypress at the start of execution.

Documentation changes (in addition to descriptions of the program changes):

• Thanks to Matthew Miner, the download now includes a Quick Reference Card for GREP. The MS-Word file GREPQRC.DOC prints on A4 or 8½×11 paper.
• The interactive demo, TOUR.BAT, used to fail if you renamed grep32.exe or grep16.exe to grep.exe as the GREP Quick Start recommends; now the tour runs. Ilustrations of the /G2 option and the new binary format are now included.
• A new chapter called Future Directions was added to the GREP Manual.
• A note was added to the GREP Manual about optimizing the order of multiple regexes in a file.
• Redirecting output with >outputfile makes GREP hang up! was added to the Troubleshooting and How-To section of the GREP Manual.
• The questions in the Troubleshooting and How-To section of the GREP Manual are now listed in the table of contents.
• At a user's request, the two CSS files in the distribution were renamed to begin with GREP. If you unpack GREP over a previous release, you should manually delete the old files print.css and screen.css.

Release 7.41, 30 Oct 2004

This release fixes two bugs that were introduced in release 7.4. Both have to do with the /J2 or /J3 option:

• GREP 7.4 had a problem with reading a partial buffer to replace a partially used buffer in a binary file. This could result in over- or under-reporting matches if you used the /R3 option with /J2 or /J3. This was not an issue if your buffer was large enough to hold the file as recommended.
• GREP 7.4 counted matches wrong for all file types with the /J2 or /J3 option. Specifically, the counts reported with the C option and the summary at the end were the sum of the number of matches and the number of lines containing matches, instead of just the number of matches. (Counts with the /J1 option or with no /J option were correct.)

Release 7.4, 23 Oct 2004

Program changes:

• The /J option is now a numeric option /J0 through /J3. When a line, record, or buffer contains one or more matches, you can now tell GREP to display the entire line, only the first matching part, or every matching part with or without overlaps.
• The /Y option and /J option make no logical sense together. Previously GREP tried to make sense of the combination; now it's just not allowed.
• The /C option and /K option are now allowed together. Perhaps you might want to count matches in the file without displaying them, but stop reading a big file if the number of hits reaches a certain value.
• GREP now displays a grand total of the number of matches, number of files containing matches, and number of files examined. (GREP with the /L option displays the number of files containing matches and the number of files examined.) This new information is written to the standard error stream, so that it won't interfere with any processing you do of the redirected output; and you can suppress it entirely with the /Q option.
• Previously, if you supplied GREP a directory name with trailing backslash, it didn't find any matching files. Now it assumes * after a trailing backslash in a filespec.
• The tour (TOUR.BAT) now lets you quit at any point, without answering N to every offered demonstration.
• bug fix: GREP /R3 /J /N was displaying the byte number of the start of the buffer. Now it displays the byte number of the start of the match, as it should.

Document changes:

• The GREP Manual describes the redesigned /J option. In addition, with the new /J2 and /J3 selections there are some changes to how free-format binary files are read (/R3 option) and to the recommended buffer width (/W option).
• The list of options in the GREP Quick Start now shows UNIX -o as equivalent to the /J option.
• The GREP Manual now warns you if you read it without its associated CSS style sheets. They provide helpful formatting and spacing, particularly in tables of regexes and options.

Release 7.31, 8 Jul 2004

Program change: Add a warning in the help message about regexes that start with - or /, in response to a user's question.

Documentation changes:

• Add the above warning to the GREP Manual in the section on regexes.
• Add a quick reference table of special characters to the regex overview in the GREP Manual.

Release 7.3, 5 Jul 2004

Program changes:

• GREP no longer strips off a pair of quotes that enclose a regex. Recent versions of DOS appear to do this automatically, and therefore you should see no difference in final processing. What will be different is that now it becomes easier to specify a regex that contains quotes, such as \"something\".
• If you specify a directory name as an input file, GREP no longer displays a warning and ignores it, but now scans all files in that directory.
• Debug output was improved: command-line arguments are now numbered, and regexes are no longer quoted in the debug output.
• Exactly one error message, "character class never ended", ended with a period; it's now consistent with the rest. "Unsupported locale" became "unsupported locale in M option". "The E3 option is accepted for E2 plus J" became "the E3 option is treated as E2 plus J".

Documentation changes:

• The user guide and reference manual were reorganized from the ground up, into a GREP Quick Start targeted at new users and a large self-contained GREP Manual with full information on all topics. Previously, the main discussions of binary files, subdirectory searches, and ERRORLEVEL were in the user guide, and some discussions were split between the two documents. Now, experienced users need search only the GREP Manual to answer any question.
• For the first time in a couple of years, both documents were reread beginning to end. A few small errors were corrected, and many clarifications and hyperlinks were added.
• Navigation in the GREP Manual should now be much easier. Sections are numbered, and each chapter now has a table of its own contents. The whacking great table of contents at the beginning was moved to the end, and at the beginning there's now a manageable list of chapters.
• Subdirectory Searches now explains the search order in full detail, with new examples.
• The Input Filespecs section of the GREP Manual now explains how to search a file whose name contains a [ character.
• The GREP Manual now explains interactions between the /L option and multiple regexes, and how to find a file that contains multiple regexes not on the same line.

Release 7.2, 13 Jan 2003

Program changes: The latest changes from PCRE release 3.9 were adapted into the code for the /E2 and /E4 options. Those changes fixed some esoteric bugs but did not add any features. (This affects only GREP32 since those options don't exist in GREP16, but the GREP16 release number was updated for consistency.)

Documentation changes:

• In response to a user query, the reference manual clarified that many options are toggles, and if used multiple times on the command line will reverse themselves.
• The GREP*.HTM documents were styled to match the Oak Road Systems Web site. As part of this, the style sheet ORSSW.CSS has been replaced by the separate style sheets SCREEN.CSS and PRINT.CSS.

Release 7.21, 12 Apr 2004, fixed a bug: when the regex contained an opening [ but no closing ], the command-line parser mistakenly diagnosed it as a bad filename instead of a bad regex.

Release 7.11, 29 Apr 2002

This release fixed a memory allocation bug that affected the /E4 option. For some regexes, an internal error was generated.

Release 7.1, 27 Mar 2002

The new /E4 option tells GREP to search for your regex as a word.

An optional second argument on the /M option now lets you define what is a "word" character, if you need to.

Release 7.02, 24 Mar 2002, was an internal checkpoint release for a few minor changes:

• Per user request, when you specify a list of input files with the /@ option leading and trailing blanks are now removed from the filespecs.

• The new value 4 is returned in ERRORLEVEL if GREP found no files to match any of your input filespecs. A warning message also appears, if you specified multiple filespecs on the command line or used the /@ option.

• The message "no files at all matched filespec" became "no files exist like filespec". This should reduce confusion with the (possibly normal) situation where the input file exists but none of its lines match the regex.

• The warning message "Some matches in the middle of long lines may have been missed. You might want to try the /Wn option" now suggests both text and binary widths, when GREP is deciding whether files are text or binary (/R-1 or /R-2 option). This is just a clarification of the warning message; there is no change in how GREP handles files.

• The reference manual says that, when an input filespec doesn't match any files, GREP reminds you to check your exclusions. In 7.0 and 7.01 the warning appeared even if you never used the /X option; now it doesn't.

Release 7.01, 10 Feb 2002

Program changes:

• The warning message "the X option is useful only with named input files" is now "the X option is ignored when reading only standard input", and is suppressed when you have /X options only in the environment variable, not on the command line.

• The warning message "the R option applies only to named files, not standard input" now appears only when you told GREP to read files in binary (R2 or R3 option), not when you told GREP to sense the file type (/R-1 or /R-2).

• In reading text files, GREP 7.01 doesn't check for error unless the read function returns a non-normal status. The way it was done in 7.0 was correct but wasted a very few CPU cycles.

Documentation changes:

• In the Troubleshooting section of the user guide, "GREP is finding too many matches!" was changed to "How do I search for a word?" New question "How do I find all files that contain 'this' and 'that'?" was added.

• The style sheet was developed further, and validated.

Release 7.0, 21 Jan 2002

As promised, this release was driven by users' responses to the poll distributed with release 6.9.

Program changes:

• Filenames have more extensive wildcards. The wildcard rules were added to the help message.

  GREP16 users, please note that ABC* now means the same thing as ABC*.*, namely all filenames that begin with ABC.

• You can use the new /@ option to give GREP a file list in a file, when a program generates your list of input files or there are simply too many for the command line.

• You can use the new /X option to exclude filenames that match certain patterns.

• The /Kcount option was added, to tell GREP to stop reading each file after reporting the first count matches.

• When no input files are named, and input is from the keyboard (not redirected from file), GREP now prompts you to enter each line. Previously, it just sat there and waited for you to realize your mistake.

• The message prompting you for regexes (/F- option) is now written directly to the console, not to standard error (which could be redirected in some operating systems.) And a prompt appears for each regex after the first.

• The text of several error and warning messages was tweaked slightly for consistency, and the help text was expanded a bit more. Customized text was removed from all "insufficient memory" messages, in favor of automatically generated file and line numbers.

Documentation changes:

• A complete list of GREP's warnings and error messages, with explanations, was added to the reference manual.

• The description of command line syntax was overhauled. Input redirection was clarified, and a section was added on output redirection. The description of named input files was greatly simplified, with the detailed (and new) rules moved to the reference manual.

• The HTML versions now use an experimental style sheet, which should make them slightly more attractive on your screen.

Release 6.9, 22 Dec 2001

This was a pre-release of 7.0. A poll distributed with this release asked users to indicate which requested features they would like to see in the program.

Program changes:

• Binary file modes have been completely overhauled. The old /R toggle has been replaced by a mode selection via the /R2 option for record-oriented binary or the /R3 option for free-format binary. This solves a known but serious problem with the old binary mode, where a match would be missed if it crossed a block boundary.

• The new /R-1 or /R-2 option lets you tell GREP to figure out on its own whether each input file is text or binary. (/R-1 and /R-2 are available only with the registered version.)

• You can now specify different widths for binary blocks and text lines with the /W option. The /W option minimum value, formerly 10 characters, is now 2.

• (GREP32 only) The new /M option allows correct case-blind matching and character classes with non-English letters and other 8-bit characters. (A test file is included.) Binary output now displays the hex value <nn> for every non-printing character, according to the current character set (/M option).

• A new demo file, TOUR.BAT, is included.

• The new /J option tells GREP to display from each line only the portion that matched the search string, basic regex, or extended regex. In release 6.0, this was added for extended regexes only, and you specified the /E3 option. /E3 is still allowed, but is equivalent to /E2 /J.

• In record-oriented binary files (/R2 option), the ^ anchor at the start and $ anchor at the end of a basic regex now mean the start and end of block, for better consistency with extended regexes.

• GREP is now about 5% faster on text files, and NUL (ASCII 0) will no longer cause the rest of a line to be ignored.

• With the /L option, GREP now stops reading a file as soon as it finds a match, unless the /V option is also set.

• Debug output now includes additional information:

  • per-file execution time and number of lines/records/buffers read
  • the maximum line length of any individual text file that exceeds the txwid in the /W option
  • total execution time, number of files scanned, and number of files that contained matches
  • the compiled form of extended regexes
  • blank lines and dashes at the start of debug output when written to a real file
     

• Bug fix: Release 6.0 began diagnosing wildcard filespecs that produce no files at all, even when the /S option (subdirectory) is set. Unfortunately, the code to do that broke the previous code that diagnosed missing single files. The code to check the various cases is now collected in one place, and diagnosis should be correct and complete.

• Bug fix: The numeric values of the /Q option were added to debug output and the help message, where they should have been for release 6.0.

Documentation changes (in addition to those driven by the above program changes):

• The user guide had grown more and more unwieldy. All the details of options and regexes are now split off into a separate reference manual, which is included in the download file but not published on the Web.

• A table of options with one-line descriptions and a summary of regexes were added to the user guide; both are hyperlinked to sections in the reference manual. This may make it easier to find the feature you need.

• Information on greedy and ungreedy quantifiers was added to the reference manual and to the help message.

• The groups of options in the reference manual and the help message were rearranged to input, pattern-matching, output, and general.

• The writeups of several options in the help message were expanded.

Release 6.0, 8 Sep 2001

Note: There were beta test releases numbered 5.95, 5.97, and 5.98. For users who participated in the beta test, a number in parentheses indicates the release where a particular change was made.

Program changes:

• (5.95) The big news is the addition of extended regular expressions. GREP can now handle constructs like alternatives |, optionals ?, general quantifiers {...}, subexpressions (...), and more. With extended regexes, you can choose whether GREP reports matching lines as usual, or just the portion of each line that matches the extended regex.

• (5.95) You can now bypass regular expressions entirely and just search for literal text.

• (5.97) You can now turn the Special Rules for the Command Line on and off.

• (5.98) You now have finer-grained control over warning messages with numeric levels for the /Q option.

• (5.97) GREP now displays a warning message for any file spec that matches no files, even if the /S option (search subdirectories) is on.

• (5.97) You can now put a plus sign after an option to turn it on (as opposed to toggling it). Example: repeated /N will flip the option between on and off, but /N+ turns on the option regardless of any previous settings.

• (5.98) Character types and assertions were added to the help message.

• (5.95) When you put a regex on the command line, you may need to enclose it in quotes, and if you do then GREP strips them (as past releases did). But, in agreement with the user guide, it no longer does that with regexes entered in a file or at the keyboard (/F option).

• (5.95) Two bugs in parsing oddly constructed character classes were fixed. (1) If you had a regex like []abc], GREP wrongly took the first square bracket as ending the class. GREP now correctly treats a ] at the beginning of a character class as an ordinary character. (2) A minus sign at the end of a class, like [abc-], is now treated correctly as a normal character.

• (5.95) The user guide told you that when your regex begins with a - or / character, you should prefix it with a \ to keep it from being taken as an option. GREP was considering that leading \ as part of the regex; it doesn't any more.

• (5.98) If you specify named input files and also redirected input (<file), GREP has always ignored the redirected input. A warning message now appears in this case.

• (5.97) The /Z option used to reset all options except the /F option; it now resets all options as documented.

User guide changes:

• (5.95) The section on regular expressions was pretty much rewritten, rather than try to shoehorn in all the stuff for extended regexes. (Only about 80% of the syntax of extended regular expressions was added to the user guide, though all is supported in the program. For a complete description, the relevant parts of the PCRE man page are also included.)

• (5.95) A section on troubleshooting was added.

• (5.97) The section on the environment variable now makes clear that /Z option resets all options including /D and /F.

• (5.97) The section on Special Rules for the Command Line was reorganized to make it clearer when you do and don't need the rules, and information was added on the new ability to turn them on and off.

Release 5.33, 19 Aug 2001

This is a repackaging for Simtel; there are no significant functional changes.

Release 5.32, 20 May 2001

If you specified current directory on another disk, such as "d:*.htm", GREP was taking that as root directory, "d:\*.htm". Apparently no one but the program author ever does such a thing!

Release 5.31, 18 April 2001

Unfortunately, a bug was introduced in release 5.3: under certain circumstances, GREP got confused about whether it was working from standard input or input files. This release corrects that bug, with my apologies to everyone who downloaded the buggy 5.3.

Release 5.3, 17 April 2001

New features:

• The new /Y option lets you search for lines that contain multiple regexes in any order.
• The /D option now allows the pseudo filename "-", for debugging display on standard output.
• Options can now appear anywhere on the command line, not just before the first file spec.

Other changes:

• If the regex began with a single or double quote but did not end with one, GREP formerly assumed you meant to put it in quotes but forgot the closing quote. Now, it interprets the quote mark as the first character of the regex.
• If GREP detects an internal error, it returns 128 in ERRORLEVEL instead of 252.
• Two facilities for "canning" GREP parameters are now restricted to the registered version of the program: the environment variable and multiple regexes from file. (Multiple regexes can still be entered "live" at the keyboard.)
• Some internal functions of the code were factored out into common routines used by multiple Oak Road Systems programs. There should be no significant change visible to users beyond the formatting of some messages.
• For people who license the source code, the build procedure was streamlined to use a single makefile.

Release 5.2, 4 Jan 2001

• In the user guide, split out the file input options and pattern-matching options from the big group of general options, and provide a road map to the plethora of output options.
• In the help message, describe the /C option and /V option a bit more explicitly, arrange the options to match the functional groups in the user guide, and add a tip about using more to paginate the message.
• In the list of option settings (displayed if you turn on the /D option, arrange the options to match the functional groups in the user guide, add the relevant option letter to each setting, and show the setting of the /1 or /0 option.
• Replace a lot of funky macros with more straightforward functions for displaying diagnostic messages, and clarify the text of a few messages.
• Tie certain features to the registered version of GREP. Make the logo and the debugging output reflect the registration status.

Release 5.1, 31 May 2000

• 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.

Release 5.0, 7 May 2000

Program changes:

• 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 messages 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

User guide changes:

• 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.

Release 4.5, 25 Sep 1999

Program changes:

• 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
• Systematize the debugging output somewhat, in the course of fixing the preceding bug
• Fix a bug: on the command line, \e in regular expressions was expanded to Control-W (octal 27) instead of Escape (decimal 27)

User guide changes: Clarify and expand "Special rules for the command line" section of the user guide, clarify the descriptions of the /D option and /I option, and add quite a few internal hyperlinks

Release 4.4, 18 Sep 1999 (limited release)

Program changes:

• Restore the /S option for searching subdirectories
• Add the /A option for searching hidden and system files

User guide changes:

• Add a section to describe input files and redirection

Release 4.3, 4 Aug 1999

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

Release 4.2, 20 Feb 1999

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

Release 4.1, 22 Jan 1999

• 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 the /P option); diagnose conflicts only after the last option has been scanned
• Take an optional output file name with the /D option (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

Release 4.0, May 1998

• 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

First shareware release: On 19 Nov 1998 the documents were updated and GREP was packaged for release, with no changes to the program.

Release 3.4, March 1998

• 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

Release 3.3, Feb 1998

• 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 (but see Release 4.4, above)
• Fix a bug: inside [...] in regular expressions, the backslash was swallowing an extra character

Release 3.2, June 1997

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

Release 3.1, Jan 1997

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

Release 3.0, Dec 1996

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

Release 2.4, April 1990

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

Release 2.3, March 1990

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

Release 2.2, Jan 1990

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

Release 2.1, Dec 1989

• 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

Release 2.0, July 1989

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

Release 1.0, April 1986

• Initial release (to clients only): Though all code was developed independently, I got some ideas from PC Tech Journal, May 1996, pages 191-199.