comm - select or reject lines common to two files
comm [-123] file1 file2
The comm utility will read file1 and file2, which should be
ordered in the current collating sequence, and produce three
text columns as output: lines only in file1; lines only in
file2; and lines in both files.
If the input files were ordered according to the collating
sequence of the current locale, the lines written will be in
the collating sequence of the original lines. If not, the
results are unspecified.
The following options are supported:
-1 Suppress the output column of lines unique to file1.
-2 Suppress the output column of lines unique to file2.
-3 Suppress the output column of lines duplicated in
file1 and file2.
The following operands are supported:
file1 A path name of the first file to be compared. If file1
is -, the standard input is used.
file2 A path name of the second file to be compared. If
file2 is -, the standard input is used.
See largefile(5) for the description of the behavior of comm
when encountering files greater than or equal to 2 Gbyte ( 2
Example 1: Printing a list of utilities specified by files
If file1, file2, and file3 each contained a sorted list of
example% comm -23 file1 file2 | comm -23 - file3
would print a list of utilities in file1 not specified by
either of the other files. The entry:
example% comm -12 file1 file2 | comm -12 - file3
would print a list of utilities specified by all three
files. And the entry:
example% comm -12 file2 file3 | comm -23 -file1
would print a list of utilities specified by both file2 and
file3, but not specified in file1.
See environ(5) for descriptions of the following environment
variables that affect the execution of comm: LANG, LC_ALL,
LC_COLLATE, LC_CTYPE, LC_MESSAGES, and NLSPATH.
The following exit values are returned:
0 All input files were successfully output as specified.
>0 An error occurred.
See attributes(5) for descriptions of the following attri-
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Availability | SUNWesu |
| CSI | enabled |
| Interface Stability | Standard |
cmp(1), diff(1), sort(1), uniq(1), attributes(5),
environ(5), largefile(5), standards(5)
Man(1) output converted with