| FC |
|
| Compares two files and displays the differences between them. |
|
| Syntax |
|
| To make an ASCII comparison, use the following syntax: |
|
| FC [/A] [/C] [/L] [/LBn] [/N] [/T] [/W] [/nnnn][drive1:][path1]filename1 |
| [drive2:][path2]filename2 |
|
| To make a binary comparison, use the following syntax: |
|
| FC /B [drive1:][path1]filename1 [drive2:][path2]filename2 |
|
| Parameters |
|
| [drive1:][path1]filename1 |
| Specifies the location and name of the first file you want to compare. |
|
| [drive2:][path2]filename2 |
| Specifies the location and name of the second file you want to compare. |
|
| Switches |
|
| /A |
| Abbreviates the output of an ASCII comparison. Instead of displaying all |
| the lines that are different, FC displays only the first and last line |
| for each set of differences. |
|
| /C |
| Ignores the case of letters. |
|
| /L |
| Compares the files in ASCII mode. FC compares the two files line by line |
| and attempts to resynchronize the files after finding a mismatch. This |
| is the default mode for comparing files that do not have extensions of |
| .EXE, .COM, .SYS, .OBJ, .LIB, or .BIN. |
|
| /LBn |
| Sets the number of lines for the internal line buffer. The default |
| length of the line buffer is 100 lines. If the files being compared have |
| more than this number of consecutive differing lines, FC cancels the |
| comparison. |
|
| /N |
| Displays the line numbers during an ASCII comparison. |
|
| /T |
| Does not expand tabs to spaces. The default behavior is to treat tabs as |
| spaces, with stops at each eighth character position. |
|
| /W |
| Compresses white space (tabs and spaces) during the comparison. If a |
| line contains many consecutive spaces or tabs, the /W switch treats |
| these characters as a single space. When used with the /W switch, FC |
| ignores (and does not compare) white space at the beginning and end of a |
| line. |
|
| /nnnn |
| Specifies the number of consecutive lines that must match before FC |
| considers the files to be resynchronized. If the number of matching |
| lines in the files is less than this number, FC displays the matching |
| lines as differences. The default value is 2. |
|
| /B |
| Compares the files in binary mode. FC compares the two files byte by |
| byte and does not attempt to resynchronize the files after finding a |
| mismatch. This is the default mode for comparing files that have |
| extensions of .EXE, .COM, .SYS, .OBJ, .LIB, or .BIN. |
|
|
| FC--Notes |
|
| Reporting differences between files for an ASCII comparison |
|
| When you use FC for an ASCII comparison, MS-DOS reports differences between |
| two files by displaying the name of the first file, followed by the last |
| line to match in both files, followed by the lines from filename1 that |
| differ between the files, followed by the first line to match in both files. |
| MS-DOS then displays the name of the second file, followed by the last line |
| to match, followed by the lines from filename 2 that differ, followed by the |
| next line to match. |
|
| Using the /B switch for binary comparisons |
|
| MS-DOS uses the following format to report mismatches found during a binary |
| comparison: |
|
| xxxxxxxx: yy zz |
|
| The value of xxxxxxxx specifies the relative hexadecimal address for the |
| pair of bytes, measured from the beginning of the file. Addresses start at |
| 00000000; the hexadecimal values for yy and zz represent the mismatched |
| bytes from filename1 and filename2, respectively. |
|
| Using wildcards |
|
| You can use wildcards (* and ?) in either of the filenames you specify with |
| the FC command. If you use a wildcard in filename1, FC compares all the |
| specified files to the file specified by filename2. If you use a wildcard in |
| filename2, FC uses the corresponding value from filename1. |
|
| How FC uses memory |
|
| When comparing ASCII files, FC uses an internal buffer (large enough to hold |
| 100 lines) as storage. If the files are larger than the buffer, FC compares |
| what it can load into the buffer. If FC does not find a match in the loaded |
| portions of the files, it stops and displays the following message: |
|
| Resynch failed. Files are too different. |
|
| When comparing binary files that are larger than available memory, FC |
| compares both files completely, overlaying the portions in memory with the |
| next portions from the disk. The output is the same as that for files that |
| fit completely in memory. |
|
|
| FC--Examples |
|
| Suppose you want to make an ASCII comparison of two text files that are |
| named MONTHLY.RPT and SALES.RPT, and you want to display the results in |
| abbreviated format. To make this comparison, type the following command: |
|
| fc /a monthly.rpt sales.rpt |
|
| To make a binary comparison of two batch files named PROFITS.BAT and |
| EARNINGS.BAT, type the following command: |
|
| fc /b profits.bat earnings.bat |
|
| The results of this command will be similar to the following: |
|
| 00000002: 72 43 |
| 00000004: 65 3A |
| 0000000E: 56 92 |
| 00000012: 6D 5C |
| 00000013: 0D 7C |
| 00000014: 0D 0A |
| 00000015: 0A 0D |
| 0000001E: 43 7A |
| 0000001F: 09 0A |
| 00000022: 72 44 |
| ... |
| ... |
| ... |
| 000005E0: 00 61 |
| 000005E1: 00 73 |
| 000005E2: 00 73 |
| 000005E3: 00 69 |
| 000005E4: 00 67 |
| 000005E5: 00 6E |
| 000005E6: 00 6D |
| 000005E7: 00 65 |
| 000005E8: 00 6E |
| FC: EARNINGS.BAT longer than PROFITS.BAT |
|
| If the PROFITS.BAT and EARNINGS.BAT files were identical, FC would display |
| the following message: |
|
| FC: no differences encountered |
|
| To compare every .BAT file in the current directory with the file NEW.BAT, |
| type the following command: |
|
| fc *.bat new.bat |
|
| To compare the file NEW.BAT on drive C with the file NEW.BAT on drive D, |
| type the following command. |
|
| fc c:new.bat d:*.bat |
|
| To compare each batch file in the root directory on drive C to the file with |
| the same name in the root directory on drive D, type the following command: |
|
| fc c:\*.bat d:\*.bat |
|
|
