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Full Discussion: Understanding Xargs
Top Forums Shell Programming and Scripting Understanding Xargs Post 303010124 by RudiC on Wednesday 27th of December 2017 05:24:23 AM
Old 12-27-2017
Now, these are very basic questions from quite broad a range of IT, and I'm not sure I can cover that to satisfaction. On top, there may be a language barrier, e.g with "occurrence". I'd advise to use a dictionary, as - to me - the meaning got immediately clear when seeing the translations. Please also consult introductory text books and / or man pages.

It might be worthwhile to internalize the concept of a string which you will encounter everywhere in IT (tools, databases, documents, files, ...) when needing to represent text. It can come in a variety of shapes, like fixed or varying length strings, zero terminated or with a leading length indicator, string constants, substrings, string concatenations, and what have you, and there are many tools, libraries, functions to handle them. Different digital items (numbers, logical values) can be output to screen as readable text representations only, not as the individual items themselves.

Then, there are text files, a loosely structured collection of (mostly) printable characters. In *nix systems, those consist of lines of characters terminated by a <new line> (\n, ^J, 0x0A) character. But this is not the only possible text representation. When reading a line from a file, you can put it into a single string variable, or split it into several substrings. If you do so by applying spaces and / or punctuation chars for separating, the substrings will be words. But any other separation is possible albeit not necessarily sensible. So, a line is sort of a superset of (a group of) strings.

A "command line" specifies a collection of a command name (perhaps including a path), zero or more options (with possible arguments), and zero or more parameters. Any of those is a (possibly one character) string, analysed by the command interpreter, and then supplied to the program being executed. Please be aware that the terms "argument" and "parameter" are not strictly distinguished between and both are loosely and interchangably used. (I neglected possible local variable assingments and redirections to avoid overcomplicaton.)
Last edited by RudiC; 12-27-2017 at 10:13 AM.. Reason: Some typos
 

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LEARN ABOUT HPUX

wc

wc(1)							      General Commands Manual							     wc(1)

NAME

       wc - count words, lines, and bytes or characters in a file

SYNOPSIS

       [file]...

DESCRIPTION

       The  command  counts lines, words, and bytes or characters in the named files, or in the standard input if no file names are specified.	It
       also keeps a total count for all named files.

       A word is a string of characters delimited by spaces, tabs, or newlines.

   Options
       recognizes the following options:

	      Report the number of bytes in each input file.

	      Report the number of newline characters in each input file.

	      Report the number of characters in each input file.

	      Report the number of words in each input file.

       The and options are mutually exclusive.	Otherwise, the and or options can be used in any combination to specify that a	subset	of  lines,
       words, and bytes or characters are to be reported.

       When any option is specified, reports only the information requested.  If no option is specified, the default output is

       When a file is specified on the command line, its name is printed along with the counts.

   Standard Output
       By default, the standard output contains an entry for each input file in the form:

	      newlines words bytes file

       If the option is specified, the number of characters replaces the bytes field in this format.

       If any option is specified, the fields for the unspecified options are omitted.

       If no file operand is specified, neither the file name nor the preceding blank character is written.

       If  more than one file operand is specified, an additional line is written at the end of the output, of the same format as the other lines,
       except that the word (in the POSIX locale) is written instead of a file name and the total of each column is written as appropriate.

       Under UNIX Standard environment, a word is a string of characters delimited by spaces, tabs, newline,  carriage-return,	vertical  tab,	or
       form-feed.

RETURN VALUE

       exits with one of the following values:

	      Successful completion.
	      An error occurred.

EXTERNAL INFLUENCES

       For information about the UNIX Standard environment, see standards(5).

   Environment Variables
       determines the range of graphics and space characters, and the interpretation of text as single- and/or multibyte characters.

       determines the language in which messages are displayed.

       If or is not specified in the environment or is null, they default to the value of

       If is not specified or is null, it defaults to (see lang(5)).

       If any internationalization variable contains an invalid setting, they all default to See environ(5).

   International Code Set Support
       Single- and multibyte character code sets are supported.  with a newline character, the count will be off by one.

WARNINGS

       The  command counts the number of newlines to determine the line count.	If a text file has a final line that is not terminated with a new-
       line character, the count will be off by one.

EXAMPLES

       Print the number of words and characters in

       The following is printed when the above command is executed:

       where words is the number of words and chars is the number of characters in

SEE ALSO

       standards(5).

STANDARDS CONFORMANCE

																	     wc(1)
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