.TH ARC 1L "12 Jun 1988" "Local" "LOCAL COMMANDS".SH NAMEarc \- pc archive utility.SH SYNOPSIS.B arca|m|u|f|d|x|e|r|p|l|v|t|c [ biswnoq ] [ g\fIpassword\fR ].I archive [ \fIfilename\fR ...].SH DESCRIPTION.I Arcis a general archive and file compression utility, used to maintaina compressed archive of files.An.I archiveis a single file that combines many files, reducing storage spaceand allowing multiple files to be handled as one..I Arcuses one of several compression methods for each file within the.IR archive ,based on whichever method yields the smallest result..SH INSTRUCTIONSExecute.I arcwith no arguments for fairly verbose, usable instructions..SH COMMAND SWITCHES.TP 3aadd files to archive.  Copies the indicated files to the archive..TPmmove files to archive.  Same as 'a' switch exceptthat the files are deleted from the directory asthey are moved to the archive..TPuupdate files in archive.  This switch will replace archivedfiles when the named file is newer than the archived copy.New files will be added automatically..TPffreshen files in archive.  Same as 'u' except thatnew files will not be added..TPddelete files in archive.  The named files are removed from the archive..TPx,eextract files from archive.  The named files are extractedfrom the archive and created in the current directoryin an uncompressed state..TPrrun one file with arguments from archive.  Anyprogram may be executed directly from the archive.The parameters given after the program name are passed tothe program without modification..TPpcopy files from archive to standard output.  Usefulwith I/O redirection. A form-feed is appended after each file,to ease use with printers..TPllist files in archive.  Limited information listingof files contained in an archive.  Displays thefilename, original length, and date last modified.If the 'n' option (see below) is used, only thefilename is displayed..TPvverbose listing of files in archive.  Completeinformation listing of files contained in an archive.Displays the filename, original length, storage method,storage factor (% savings), compressed size, date, time,and CRC..TPttest archive integrity.  Computes CRC values for each member ofthe archive and compares against the previously saved value..TPcconvert entry to new packing method.  Convert filesstored with older methods to newer methods that aremore efficient. Also useful for files previouslyarchived with the 's' option..SH OPTIONS.TP 3bretain backup copy of archive.  Keep the originalarchive file and rename to .BAK.This switch may be used with thefollowing commands:  a, m, u, f, d, c..TPisuppress image mode.  This switch causes files tobe treated as text files, and will translate theirend-of-line sequence. (Unix's '\\n' vs. '\\r\\n' usedon many other systems.)  The default is to performno translation when compressing or extracting files.This option makes dealing with text files much nicer,though the 'tr' command can also be used. ('\\r' inmakefiles and C source code is such a nuisance...).TPssuppress compression.  This forces new files to besaved using Method 2 (no compression).  This switchmay be used with the following commands:  a, m, u, f, c..TPwsuppress warning messages.  This switch will keepwarning messages from being displayed which is the default.Most warnings concern the deletion or existence offiles with the same name..TPnsuppress notes and comments.  This switch will keepuseful notes from being displayed which is the default.Most notes indicate what stage of compression isbeing run (analyze, compaction, storage)..TPooverwrite existing files when extracting.  This switchwill make existing files silently get overwritten, insteadof asking for confirmation, which is the default..TPqforce Squash compression method.  This switch causesthe Squash compression method to be used, instead ofCrunch, which is the default..TPgencrypt/decrypt archive entry.  This is used to encodefiles so that others may not read them.  BE CAREFUL!This must be the last parameter in the switches becauseeverything following is part of the password..SH PROGRAMMING NOTES.I ArcVersion 2 differs from version 1 in that archive entriesare automatically compressed when they are added to the archive,making a separate compression step unecessary.  The nature of thecompression is indicated by the header version number placed ineach archive entry, as follows:.nf         1 = Old style, no compression         2 = New style, no compression         3 = Compression of repeated characters only         4 = Compression of repeated characters plus Huffman SQueezing         5 = Lempel-Zev packing of repeated strings (old style)         6 = Lempel-Zev packing of repeated strings (new style)         7 = Lempel-Zev Williams packing with improved hash function         8 = Dynamic Lempel-Zev packing with adaptive reset         9 = Squashing.fiType 5, Lempel-Zev packing, was added as of version 4.0Type 6 is Lempel-Zev packing where runs of repeated charactershave been collapsed, and was added as of version 4.1Type 7 is a variation of Lempel-Zev using a different hashfunction which yields speed improvements of 20-25%, and wasadded as of version 4.6Type 8 is a different implementation of Lempel-Zev, using avariable code size and an adaptive block reset, and was addedas of version 5.0Type 9 is another variation of Lempel-Zev, using a largerhash table. This method was developed by Phil Katz, and isnot supported by the "official" \fBARC\fP programs..I Arcwill look for environment variables named \fIARCTEMP\fP or\fITMPDIR\fP, which, if present, indicates the pathnamewhere temporary files should be created. This is typicallythe location of a RAMdisk on a microcomputer, "/tmp/" orleft unset.See the included documentation file for more details..SH HISTORY\fIArc\fP has been in use in the CP/M and MSDOS world for many years.Thom Henderson developed the original version, but it is important to note that\fIarc\fP is based on the file compression theories developed by Huffman, Welch,Knott, Knuth, and many other scientists. This implementation is based onversion 5.21 of the MSDOS program..SH BUGS\fIArc\fP behaves just like the PC version of the program; all functionsof the "usage" display are working.Full compatibility with PC ARC files is maintained, the price for which isthat \fIarc\fP doesn't like long filenames, and can only archive files withnames of up to 12 characters.It will *sometimes* do The Right Thing with them, but I suggestyou put long-winded filenames in a "shar" before.IR arc ingthem.There shouldn't be any problems, (hah!) but if you find any, pleasesend them to me at:	hyc@umix.cc.umich.edu	{rutgers, uunet}!umix!hyc.SH AUTHORSOriginal MSDOS program by Thom Henderson.brCOPYRIGHT(C) 1985-87 by System Enhancement Associates; ALL RIGHTS RESERVEDOriginal Lempel-Zev code derived from compress 4.0.Modified to support Squashing by Dan Lanciani (ddl@harvard.edu)Ported from MSDOS by Howard Chu (umix!hyc),with help from John Gilmore (hoptoad!gnu), James Turner (daisy!turner)and others.