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diff --git a/man-pages-posix-2017/man1p/comm.1p b/man-pages-posix-2017/man1p/comm.1p new file mode 100644 index 0000000..1e610de --- /dev/null +++ b/man-pages-posix-2017/man1p/comm.1p @@ -0,0 +1,386 @@ +'\" et +.TH COMM "1P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.\" +.SH NAME +comm +\(em select or reject lines common to two files +.SH SYNOPSIS +.LP +.nf +comm \fB[\fR-123\fB] \fIfile1 file2\fR +.fi +.SH DESCRIPTION +The +.IR comm +utility shall read +.IR file1 +and +.IR file2 , +which should be ordered in the current collating sequence, and produce +three text columns as output: lines only in +.IR file1 , +lines only in +.IR file2 , +and lines in both files. +.P +If the lines in both files are not ordered according to the collating +sequence of the current locale, the results are unspecified. +.P +If the collating sequence of the current locale does not have a total +ordering of all characters (see the Base Definitions volume of POSIX.1\(hy2017, +.IR "Section 7.3.2" ", " "LC_COLLATE") +and any lines from the input files collate equally but are not identical, +.IR comm +should treat them as different lines but may treat them as being the +same. If it treats them as different, +.IR comm +should expect them to be ordered according to a further byte-by-byte +comparison using the collating sequence for the POSIX locale and if +they are not ordered in this way, the output of +.IR comm +can identify such lines as being both unique to +.IR file1 +and unique to +.IR file2 +instead of being in both files. +.SH OPTIONS +The +.IR comm +utility shall conform to the Base Definitions volume of POSIX.1\(hy2017, +.IR "Section 12.2" ", " "Utility Syntax Guidelines". +.P +The following options shall be supported: +.IP "\fB\-1\fP" 10 +Suppress the output column of lines unique to +.IR file1 . +.IP "\fB\-2\fP" 10 +Suppress the output column of lines unique to +.IR file2 . +.IP "\fB\-3\fP" 10 +Suppress the output column of lines duplicated in +.IR file1 +and +.IR file2 . +.SH OPERANDS +The following operands shall be supported: +.IP "\fIfile1\fR" 10 +A pathname of the first file to be compared. If +.IR file1 +is +.BR '\-' , +the standard input shall be used. +.IP "\fIfile2\fR" 10 +A pathname of the second file to be compared. If +.IR file2 +is +.BR '\-' , +the standard input shall be used. +.P +If both +.IR file1 +and +.IR file2 +refer to standard input or to the same FIFO special, block special, or +character special file, the results are undefined. +.SH STDIN +The standard input shall be used only if one of the +.IR file1 +or +.IR file2 +operands refers to standard input. See the INPUT FILES section. +.SH "INPUT FILES" +The input files shall be text files. +.SH "ENVIRONMENT VARIABLES" +The following environment variables shall affect the execution of +.IR comm : +.IP "\fILANG\fP" 10 +Provide a default value for the internationalization variables that are +unset or null. (See the Base Definitions volume of POSIX.1\(hy2017, +.IR "Section 8.2" ", " "Internationalization Variables" +for the precedence of internationalization variables used to determine +the values of locale categories.) +.IP "\fILC_ALL\fP" 10 +If set to a non-empty string value, override the values of all the +other internationalization variables. +.IP "\fILC_COLLATE\fP" 10 +.br +Determine the locale for the collating sequence +.IR comm +expects to have been used when the input files were sorted. +.IP "\fILC_CTYPE\fP" 10 +Determine the locale for the interpretation of sequences of bytes of +text data as characters (for example, single-byte as opposed to +multi-byte characters in arguments and input files). +.IP "\fILC_MESSAGES\fP" 10 +.br +Determine the locale that should be used to affect the format and +contents of diagnostic messages written to standard error. +.IP "\fINLSPATH\fP" 10 +Determine the location of message catalogs for the processing of +.IR LC_MESSAGES . +.SH "ASYNCHRONOUS EVENTS" +Default. +.SH STDOUT +The +.IR comm +utility shall produce output depending on the options selected. If the +.BR \-1 , +.BR \-2 , +and +.BR \-3 +options are all selected, +.IR comm +shall write nothing to standard output. +.P +If the +.BR \-1 +option is not selected, lines contained only in +.IR file1 +shall be written using the format: +.sp +.RS 4 +.nf + +"%s\en", <\fIline in file1\fR> +.fi +.P +.RE +.P +If the +.BR \-2 +option is not selected, lines contained only in +.IR file2 +are written using the format: +.sp +.RS 4 +.nf + +"%s%s\en", <\fIlead\fR>, <\fIline in file2\fR> +.fi +.P +.RE +.P +where the string <\fIlead\fP> is as follows: +.IP <tab> 10 +The +.BR \-1 +option is not selected. +.IP "null\ string" 10 +The +.BR \-1 +option is selected. +.P +If the +.BR \-3 +option is not selected, lines contained in both files shall be written +using the format: +.sp +.RS 4 +.nf + +"%s%s\en", <\fIlead\fR>, <\fIline in both\fR> +.fi +.P +.RE +.P +where the string <\fIlead\fP> is as follows: +.IP <tab><tab> 10 +Neither the +.BR \-1 +nor the +.BR \-2 +option is selected. +.IP <tab> 10 +Exactly one of the +.BR \-1 +and +.BR \-2 +options is selected. +.IP "null\ string" 10 +Both the +.BR \-1 +and +.BR \-2 +options are selected. +.P +If the input files were ordered according to the collating sequence of +the current locale, the lines written shall be in the collating +sequence of the current locale. If the input files contained any +lines that collated equally but were not identical and within each +file those lines were ordered according to a further byte-by-byte +comparison using the collating sequence for the POSIX locale, and +.IR comm +treated them as different lines, then lines written that collate +equally but are not identical should be ordered according to a further +byte-by-byte comparison using the collating sequence for the POSIX +locale. +.SH STDERR +The standard error shall be used only for diagnostic messages. +.SH "OUTPUT FILES" +None. +.SH "EXTENDED DESCRIPTION" +None. +.SH "EXIT STATUS" +The following exit values shall be returned: +.IP "\00" 6 +All input files were successfully output as specified. +.IP >0 6 +An error occurred. +.SH "CONSEQUENCES OF ERRORS" +Default. +.LP +.IR "The following sections are informative." +.SH "APPLICATION USAGE" +If the input files are not properly presorted, the output of +.IR comm +might not be useful. +.P +When using +.IR comm +to process pathnames, it is recommended that LC_ALL, or at least +LC_CTYPE and LC_COLLATE, are set to POSIX or C in the environment, +since pathnames can contain byte sequences that do not form valid +characters in some locales, in which case the utility's behavior would +be undefined. In the POSIX locale each byte is a valid single-byte +character, and therefore this problem is avoided. +.P +If the collating sequence of the current locale does not have a total +ordering of all characters, this can affect the behavior of +.IR comm +in the following ways: +.IP " *" 4 +If +.IR comm +treats lines as being the same only if they are identical, some lines +can be misleadingly identified as being both unique to +.IR file1 +and unique to +.IR file2 . +.IP " *" 4 +If +.IR comm +treats lines as being the same if they collate equally and a line from +.IR file1 +collates equally with a line from +.IR file2 +but is not identical to it, one of the lines is misleadingly +identified as being in both files and the other is not written to the +output at all. +.P +Such problems can be avoided by forcing the use of the POSIX locale; +for example, the following identifies lines in both +.IR file1 +and +.IR file2 : +.sp +.RS 4 +.nf + +LC_ALL=POSIX sort file1 > file1.posix +LC_ALL=POSIX sort file2 > file2.posix +LC_ALL=POSIX comm -12 file1.posix file2.posix | sort +.fi +.P +.RE +.P +The final +.IR sort +re-sorts the output of +.IR comm +according to the collating sequence of the original locale. Doing +this might be difficult if more than one column is output and leading +<blank>s +cannot be ignored. +.SH EXAMPLES +If a file named +.BR xcu +contains a sorted list of the utilities in this volume of POSIX.1\(hy2017, a file named +.BR xpg3 +contains a sorted list of the utilities specified in the X/Open +Portability Guide, Issue 3, and a file named +.BR svid89 +contains a sorted list of the utilities in the System V Interface +Definition Third Edition: +.sp +.RS 4 +.nf + +comm -23 xcu xpg3 | comm -23 - svid89 +.fi +.P +.RE +.P +would print a list of utilities in this volume of POSIX.1\(hy2017 not specified by either of the +other documents: +.sp +.RS 4 +.nf + +comm -12 xcu xpg3 | comm -12 - svid89 +.fi +.P +.RE +.P +would print a list of utilities specified by all three documents, and: +.sp +.RS 4 +.nf + +comm -12 xpg3 svid89 | comm -23 - xcu +.fi +.P +.RE +.P +would print a list of utilities specified by both XPG3 and the SVID, +but not specified in this volume of POSIX.1\(hy2017. +.SH RATIONALE +None. +.SH "FUTURE DIRECTIONS" +A future version of this standard may require that if any lines from +the input files collate equally but are not identical, then +.IR comm +treats them as different lines and expects them to be ordered +according to a further byte-by-byte comparison using the collating +sequence for the POSIX locale. +.P +A future version of this standard may require that if the input files +contained any lines that collated equally but were not identical and +within each file those lines were ordered according to a further +byte-by-byte comparison using the collating sequence for the POSIX +locale, then lines written that collate equally but are not identical +are ordered according to a further byte-by-byte comparison using the +collating sequence for the POSIX locale. +.SH "SEE ALSO" +.IR "\fIcmp\fR\^", +.IR "\fIdiff\fR\^", +.IR "\fIsort\fR\^", +.IR "\fIuniq\fR\^" +.P +The Base Definitions volume of POSIX.1\(hy2017, +.IR "Section 7.3.2" ", " "LC_COLLATE", +.IR "Chapter 8" ", " "Environment Variables", +.IR "Section 12.2" ", " "Utility Syntax Guidelines" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +In the event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . +.PP +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |