dk-lines manual

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dk-lines — Select text lines

• dk-lines — Select text lines
  • Synopsis
  • Description
  • Options
  • Exit status
  • Restrictions
  • Notes
  • Examples
    • Find files modified in a specified range of dates
    • Find files modified today
    • Find 10 newest files (last modified)
    • Find 10 oldest files (by modification date)
    • Show file contents, omit first 3 and final 2 lines

Synopsis

dk-lines [_options_] [_file(s)_]

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Description

The program extracts specified lines from a text obtained from the specified files or standard input. It is mainly intended for the Windows platforms, as I do not know about an UTF-16 aware version of "head" or "tail" programs for Windows.

There are 2 processing stages, both stages are optional.

Stage 1: Text at beginning of line.
In the first stage the beginning of each text line is compared against a start text and/or an end text. Lines from within the range (including the borders) are transferred to stage 2. If only start or end text is specified, a simple comparison is used instead of the range check.

Stage 2: Line numbers.
The second stage selects lines from stage 1 output by line numbers. A start line number and/or an end line number can be specified. Positive line numbers are counted from the first line (line number 1) forwards. Negative line numbers are counted from the final line (line number -1) backwards.

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Options

Option	Purpose
-f text --from=text	Start text for stage 1.
-t text --to=text	End text for stage 1.
--today	Specify the current date in YYYY-MM-DD notation for start and end text unless specified using -t or -f. You can not use --today if both -t and -f are specified.
-l range --lines=range	Specify the line number range for stage 2.
-o --one-stream	For multiple input files, group the stage 1 results from all files before applying stage 2. Without this option the line number range is applied to each file individually.
-i string ‑‑input‑encoding=string	Expected input encoding, see the Encoding names table below. The encoding specified here is overwritten, if a BOM (byte order marker) is found at start of input. The default is the systems native encoding and endianness. The default is the systems native encoding and endianness.
‑‑line‑size=size	Line buffer size different from the default (4096 bytes).
-v --verbose	Verbose diagnostics.

Range specifiction	Example	Selection
s		Specify start line number s.
	5	Line 5 and all following lines.
	-2	Final two lines.
s/e	Specify start line number s and end line number e.
	5/10	Lines 5 to 10.
	5/-2	Lines from line 5 until (including) penultimate line.
	-5/-2	Range from fifth line from end to penultimate line.
/e	Specify just end line number e.
	/5	Lines from beginning until (including) line 5.
	/-2	Lines from beginning until (including) the penultimate line.

Name	Encoding
plain	Bytes 0x00 to 0xFF represent 32 bit characters U+00000000 to U+000000FF.
win1252	Windows codepage 1252 used by GUI applications on Windows. Formerly named ansi as the Visual Studio documentation names the functions handling such strings as ANSI versions.
utf-8 utf8	UTF-8
utf-16 utf16	UTF-16 in the systems default endianness
utf-16-le utf-16le utf16le utf-16-lsb &utf-16lsb utf16lsb	UTF-16 little-endian (least significant byte first)
utf-16-be utf-16be utf16be utf-16-msb utf-16msb utf16msb	UTF-16 big-endian (most significant byte first)
c32	32 bit UNICODE in the systems default endianness
c32-le c32le c32-lsb c32lsb	32 bit UNICODE little-endian (least significant byte first)
c32-be c32be c32-msb c32msb	32 bit UNICODE big-endian (most significant byte first)

When producing UTF-16 or 32 bit UNICODE output a BOM is written at start of output. You can suppress the BOM by appending "nobom" to the encoding, i.e. "-o utf-16-le,nobom".
To require a BOM you can append "bom" to the encoding, i.e. "-o utf-8,bom".

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Exit status

0 on success, all other status codes indicate an error.

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Restrictions

On Windows the file name length is restricted to _MAX_PATH (260) characters if the file name contains a wildcard (* or ? character).

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Notes

This program uses DK libraries version 4.

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Examples

Find files modified in a specified range of dates

To find files modified in a specified range of dates:

dk-ls -pmn -tf -r | dk-lines --from=2017-11-18 --to=2017-11-19

Program	Option	Purpose
dk-ls		List files.
	-pmn	Configure output columns: m Modification timestamp n File name
	-tf	Restrict output to files (non-directory items).
	-r	Recursive listing including all subdirectories.
dk-lines		Extract specific lines from text stream.
	--from=2017-11-18 --to=2017-11-19	Only those lines beginning with text from (inclusive) "2017-11-18" to (inclusive) "2017-11-19".

Find files modified today

To find files modified today:

dk-ls -pmn -tf -r | dk-lines --today

Option	Purpose
--today	Extract only thos lines beginning with yyyy-mm-dd (current date).

Find 10 newest files (last modified)

To find 10 newest files (last modified):

dk-ls -pmn -tf -r | dk-sort | dk-lines -l -10

Option	Purpose
-l -10	Begin extraction at line 10 before the end.

Find 10 oldest files (by modification date)

To find 10 oldest files (by modification date):

dk-ls -pmn -tf -r | dk-sort | dk-lines -l 1/10

Option	Purpose
-l 1/10	Extract line number 1 to 10.

Show file contents, omit first 3 and final 2 lines

To show file x.txt contents, omit first 3 and final 2 lines:

dk-lines -l 4/-3 x.txt

Option	Purpose
-l 4/-3	Start at line 4 from the beginning, stop at line 3 before the end.

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