NAME

combine, combine2 − compare or combine 2 or 3 source files

SYNOPSIS

combine [−BbHhqs] [−c #,#] [−d flag] [−L #] [−P #] [−p #] [−1 text] [−2 text]
old_file new1_file [new2_file]

combine2 temp_file merged_file

DESCRIPTION

combine compares the differences between 2 or 3 source files and produces a result file.  Where old_file is the name of the original file, new1_file is a file containing modifications to old_file, and new2_file is a file containing a different set of modifications to old_file.  The option arguments are:

−H Help option -- Print a brief help message and exit. 

−b Blank compress option -- Causes combine to treat all sequences of blanks and horizontal tabs as a single blank. 

−B Blank remove option -- Causes combine to ignore all blanks and horizontal tabs in a line when comparing lines. 

−c #,# Column specification option -- Specifies the column range to be compared.  By default, all columns are compared.  The number of the first column to compare immediately follows the −c option.  The number of the last column to compare is separated from the first column to compare by a comma.  Up to 32 different column ranges may be given.  For example,       combine −c10,20 a b c compares only columns 10 through 20.

−d flag Debug options -- specifies how much debug information is to be output.  The possibilities are: −d1, pass1 debug; −d2, pass2 debug; −d3, pass3 debug; −d4, pass4 debug; −d5, pass5 debug; and −da, all debug. 

−h h option -- produces a composite file on standard output suitable for input into combine2(1).  The file is an ASCII text file which may be manually modified by an text editor such as vi(1).  The example below describes the use of this option in detail. 

−L # Lines option -- Specify the number of lines to be printed on a page of the standard output file.  Specifying zero lines (−L0) disables pagination of the output file. The default page length is 66 lines.  This option is used only if the −h option is not specified. 

−p # Postfix option -- The number of unchanged lines to output to the standard output file following any group of changed lines.  The number of unchanged lines is specified by the argument following the −p option. The default is 5.  This option is used only if the −h option is not specified. 

−P # Prefix option -- The number of unchanged lines to output to the standard output file prior to any group of changed lines.  The number of unchanged lines is specified by the argument following the −P option. The default is 5.  This option is used only if the −h option is not specified. 

−q Quiet option -- Specifies that no output is to be generated to the standard output file if no changes are detected. 

−s Statistics option -- Specifies that performance statistics are to be output to standard output when combine is finished. 

−1 text New1 file description -- Symbolic description of the new1 file. This text is printed as the description of the new1 file on the listing output and h option output file. 

−2 text New2 file description -- Symbolic description of the new2 file. This text is printed as the description of the new1 file on the listing output and h option output file. 

EXAMPLE

combine may be used to perform a simple two file comparison.  by merely omitting the name of the third file. 

combine is best suited to do a three file comparison.  Consider a file which is being modified along two development paths.  The original copy of the file with no modifications is called the old file.  The copy modified along one development path is called the new1 file.  The copy modified along the other development path is called the new2 file.  The following is a guide for producing a merged file which contains both set of modifications. 
 
First, combine is called with the following command line:    combine −h old new1 new2 >temp_file The temp_file contains all of the lines from the old, new1 and new2 files combined with control lines. A control line identifies those portions of the temp_file which represent modifications made by the new1 and new2 files. 
 
Text which is inserted by the new1 or new2 file is surrounded by an ~~Insert line and an ~End line. The ~~Insert line also contains comments indicating which of the two files the inserted lines came from and whether the insertion was involved in a ‘move’ operation.  In the example below, the line ‘apple’ was inserted between two already existing lines ‘bob’ and ‘fred’.      bob
    ~~Insert ’file2’
    apple
    ~End of changes
    fred Text which is deleted by the new1 or new2 file is surrounded by an ~~Delete line and an ~End line. The ~~Delete line also contains comments indicating which of the two files deleted the specified lines an whether the deletion is a side effect of a ‘move’ operation.  In the example below, the line ‘apple’ was deleted from between the lines ‘bob’ and ‘fred’.      bob
    ~~Delete ’file1’
    apple
    ~End of changes
    fred The temp_file may be edited with any text editor. Changes in the temp_file can easily be found by finding lines with two tildes (~~) on them. Changes which are correct should be left alone. Changes which are wrong should be fixed. Deleted text can be allowed to remain in the file by merely deleting the ~~Delete line. Things to watch out for during this process include: Lines which are inserted by both the new1 and new2 files, and lines which are deleted by both the new1 and new2 files. 
 
After all of the changes have been made in the tempfile, combine2(1) should be used to produce the merged file.  Combine2(1) is called with the following command line:       combine2 temp_file merged_file Combine2(1) produces a merged file by removing the control lines and the deleted lines from the temp file. If the name of the temp file is omitted, standard input is used. If the name of the merged file is omitted, standard output is used. 

SEE ALSO

cmp(1), combine2(1), comm(1), diff(1), diff3(1)

DIAGNOSTICS

Exit status is 0 for files identical, 1 for some differences, 2 for errors. 

AUTHOR

Clifford P. Van Dyke

BUGS

Does not allow input file to be specified as − to indicate stdin. 
 
Does not allow comparison of binary files. Does not always complain if an input file is a binary file.
 
Does not check to see if two files have the same inode.

CX/UX User’s Reference Manual