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diff --git a/coreutils-5.3.0-bin/man/cat1p/tail.1p.txt b/coreutils-5.3.0-bin/man/cat1p/tail.1p.txt new file mode 100644 index 0000000..30b5852 --- /dev/null +++ b/coreutils-5.3.0-bin/man/cat1p/tail.1p.txt @@ -0,0 +1,253 @@ +tail(P) tail(P) + + + + + +NAME + tail - copy the last part of a file + +SYNOPSIS + tail [-f][ -c number| -n number][file] + +DESCRIPTION + The tail utility shall copy its input file to the stan- + dard output beginning at a designated place. + + Copying shall begin at the point in the file indicated + by the -c number or -n number options. The option-argu- + ment number shall be counted in units of lines or bytes, + according to the options -n and -c. Both line and byte + counts start from 1. + + Tails relative to the end of the file may be saved in an + internal buffer, and thus may be limited in length. Such + a buffer, if any, shall be no smaller than {LINE_MAX}*10 + bytes. + +OPTIONS + The tail utility shall conform to the Base Definitions + volume of IEEE Std 1003.1-2001, Section 12.2, Utility + Syntax Guidelines. + + The following options shall be supported: + + -c number + The application shall ensure that the number + option-argument is a decimal integer whose sign + affects the location in the file, measured in + bytes, to begin the copying: + Sign Copying Starts + + Relative to the beginning of the file. + - Relative to the end of the file. + none Relative to the end of the file. + + The origin for counting shall be 1; that is, -c +1 rep- + resents the first byte of the file, -c -1 the last. + + -f If the input file is a regular file or if the + file operand specifies a FIFO, do not terminate + after the last line of the input file has been + copied, but read and copy further bytes from the + input file when they become available. If no file + operand is specified and standard input is a + pipe, the -f option shall be ignored. If the + input file is not a FIFO, pipe, or regular file, + it is unspecified whether or not the -f option + shall be ignored. + + -n number + This option shall be equivalent to -c number, + except the starting location in the file shall be + measured in lines instead of bytes. The origin + for counting shall be 1; that is, -n +1 repre- + sents the first line of the file, -n -1 the last. + + + If neither -c nor -n is specified, -n 10 shall be + assumed. + +OPERANDS + The following operand shall be supported: + + file A pathname of an input file. If no file operands + are specified, the standard input shall be used. + + +STDIN + The standard input shall be used only if no file oper- + ands are specified. See the INPUT FILES section. + +INPUT FILES + If the -c option is specified, the input file can con- + tain arbitrary data; otherwise, the input file shall be + a text file. + +ENVIRONMENT VARIABLES + The following environment variables shall affect the + execution of tail: + + LANG Provide a default value for the internationaliza- + tion variables that are unset or null. (See the + Base Definitions volume of IEEE Std 1003.1-2001, + Section 8.2, Internationalization Variables for + the precedence of internationalization variables + used to determine the values of locale cate- + gories.) + + LC_ALL If set to a non-empty string value, override the + values of all the other internationalization + variables. + + LC_CTYPE + 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). + + LC_MESSAGES + Determine the locale that should be used to + affect the format and contents of diagnostic mes- + sages written to standard error. + + NLSPATH + Determine the location of message catalogs for + the processing of LC_MESSAGES . + + +ASYNCHRONOUS EVENTS + Default. + +STDOUT + The designated portion of the input file shall be writ- + ten to standard output. + +STDERR + The standard error shall be used only for diagnostic + messages. + +OUTPUT FILES + None. + +EXTENDED DESCRIPTION + None. + +EXIT STATUS + The following exit values shall be returned: + + 0 Successful completion. + + >0 An error occurred. + + +CONSEQUENCES OF ERRORS + Default. + + The following sections are informative. + +APPLICATION USAGE + The -c option should be used with caution when the input + is a text file containing multi-byte characters; it may + produce output that does not start on a character bound- + ary. + + Although the input file to tail can be any type, the + results might not be what would be expected on some + character special device files or on file types not + described by the System Interfaces volume of + IEEE Std 1003.1-2001. Since this volume of + IEEE Std 1003.1-2001 does not specify the block size + used when doing input, tail need not read all of the + data from devices that only perform block transfers. + +EXAMPLES + The -f option can be used to monitor the growth of a + file that is being written by some other process. For + example, the command: + + + tail -f fred + + prints the last ten lines of the file fred, followed by + any lines that are appended to fred between the time + tail is initiated and killed. As another example, the + command: + + + tail -f -c 15 fred + + prints the last 15 bytes of the file fred, followed by + any bytes that are appended to fred between the time + tail is initiated and killed. + +RATIONALE + This version of tail was created to allow conformance to + the Utility Syntax Guidelines. The historical -b option + was omitted because of the general non-portability of + block-sized units of text. The -c option historically + meant "characters", but this volume of + IEEE Std 1003.1-2001 indicates that it means "bytes". + This was selected to allow reasonable implementations + when multi-byte characters are possible; it was not + named -b to avoid confusion with the historical -b. + + The origin of counting both lines and bytes is 1, match- + ing all widespread historical implementations. + + The restriction on the internal buffer is a compromise + between the historical System V implementation of 4096 + bytes and the BSD 32768 bytes. + + The -f option has been implemented as a loop that sleeps + for 1 second and copies any bytes that are available. + This is sufficient, but if more efficient methods of + determining when new data are available are developed, + implementations are encouraged to use them. + + Historical documentation indicates that tail ignores the + -f option if the input file is a pipe (pipe and FIFO on + systems that support FIFOs). On BSD-based systems, this + has been true; on System V-based systems, this was true + when input was taken from standard input, but it did not + ignore the -f flag if a FIFO was named as the file oper- + and. Since the -f option is not useful on pipes and all + historical implementations ignore -f if no file operand + is specified and standard input is a pipe, this volume + of IEEE Std 1003.1-2001 requires this behavior. However, + since the -f option is useful on a FIFO, this volume of + IEEE Std 1003.1-2001 also requires that if standard + input is a FIFO or a FIFO is named, the -f option shall + not be ignored. Although historical behavior does not + ignore the -f option for other file types, this is + unspecified so that implementations are allowed to + ignore the -f option if it is known that the file cannot + be extended. + + This was changed to the current form based on comments + noting that -c was almost never used without specifying + a number and that there was no need to specify -l if -n + number was given. + +FUTURE DIRECTIONS + None. + +SEE ALSO + head + +COPYRIGHT + Portions of this text are reprinted and reproduced in + electronic form from IEEE Std 1003.1, 2003 Edition, + Standard for Information Technology -- Portable Operat- + ing System Interface (POSIX), The Open Group Base Speci- + fications Issue 6, Copyright (C) 2001-2003 by the Insti- + tute 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.open- + group.org/unix/online.html . + + + +POSIX 2003 tail(P) |