sdiff Command

Purpose

Compares two files and displays the differences in a side-by-side format.

Syntax

sdiff [  -l | -s ] [  -o OutFile ] [  -w Number ] File1 File2

Description

The sdiff command reads the files specified by the File1 and File2 parameters, uses the diff command to compare them, and writes the results to standard output in a side-by-side format. The sdiff command displays each line of the two files with a series of spaces between them if the lines are identical. It displays a < (less than sign) in the field of spaces if the line only exists in the file specified by the File1 parameter, a > (greater than sign) if the line only exists in the file specified by the File2 parameter, and a | (vertical bar) for lines that are different.

When you specify the -o flag, the sdiff command merges the files specified by the File1 and File2 parameters and produces a third file.

Note: The sdiff command invokes the diff -b command to compare two input files. The -b flag causes the diff command to ignore trailing spaces and tab characters and to consider other strings of spaces as equal.

Flags

Examples

1. To print a comparison of two files, enter:

   sdiff chap1.bak chap1 

   The sdiff command displays a side-by-side listing that compares each line of the chap1.bak and chap1 files.
2. To display only the lines that differ, enter:

   sdiff  -s  -w 80 chap1.bak chap1

   The sdiff command displays the differences at the work station. The -w 80 flag and variable sets the page width to 80 columns. The -s flag indicates lines that are identical in both files will not be displayed.
3. To selectively combine parts of two files, enter:

   sdiff  -s  -w 80  -o chap1.combo chap1.bak chap1

   The sdiff command combines the chap1.bak and chap1 files into a new file called chap1.combo. For each group of differing lines, the sdiff command prompts you which group to keep or whether you want to edit them using the ed command.
4. To combine and edit two files, staff.jan and staff.apr, and write the results to the staff.year file, perform the steps indicated.

   The staff.jan file contains the following lines:

   Members of the Accounting Department
   Andrea
   George
   Karen
   Sam
   Thomas

   The staff.apr file contains the following lines:

   Members of the Accounting Department
   Andrea
   Fred
   Mark
   Sam
   Wendy

   1. Enter the following command:

      sdiff -o staff.year staff.jan staff.apr

      The sdiff command will begin to compare the contents of the staff.jan and staff.apr files and write the results to the staff.year file. The sdiff command displays the following:

      Members of the Accounting Dept   Members of the Accounting Dept
      Andrea                            Andrea
      George                          | Fred
      %

      The % (percent sign) is the command prompt.
   2. Enter the e b subcommand to start editing the output file with the ed command.

      The sdiff command displays a sequence of digits, indicating the byte count of lines being merged. In this case, the byte count is 23.

   3. Enter the q subcommand to exit the ed command and continue combining and editing the two files. The sdiff command displays the following:

      Sam                              Sam
      Thomas                          | Wendy
        

   4. Enter the e b subcommand again. The ed command must be run each time a set of lines from the original two files are to be merged into the output file. The byte count in this instance is 13.
   5. Enter the q subcommand to save the changes. When all the lines of the two files have been merged into the output file, the q subcommand exits the ed and sdiff commands.
   The staff.year file now contains the following:

   Members of the Accounting Department
   Andrea
   George
   Karen
   Fred
   Mark
   Sam
   Thomas
   Wendy

Files