I'm not sure I got you right: there's absolutely no alleged "language barrier"; why the word "occurrence" caught your eye I didn't get either. That was not some kind of mistyping (which would be a common thing among both native and non-native English speakers even then and certainly would not be the worst one to consider it intolerable). I use dictionaries well enough when I deem it necessary. Thank you for your advise.

I think I made it unambiguously clear when I referenced man pages in all of my earlier posts. I suppose you have a solid tech background so I guess for you the language of man pages is anything but non-perceptible. However for many people lacking that level of expertise some phrases, terms, word choices, word combinations and the overall jargon those pages are written in, feel very painful and so are those "introductory books" written by the extra-class specialists, apparently reckoned on individuals sharing the same level of knowledge, these specialists failing to render the material in a way more acceptable by general audience; on the other hand those few that attempt to do that often fall victims of incoherent, inconsistent, over-simplified, too rushed manner of unfolding of instructional material. I suppose this forums were not designed to serve concerns of a tiny stratum of élite expertise bearing IT-specialists only. Everyone can read any manual or watch a tutorial but not everyone is guaranteed to understand it. That's why forums exist: for these persons to get opportunity to raise their issues and expect their questions to be addressed. And if not then what's the point of the forums such as this one at all?

I thought (and I really meant to) I started my thread in "Beginners" section of this forum but for some reason it was moved to Shell and Programming though the very fact of someone asking about xargs by no means implies the person asking it is a shell programmer and neither am I. My level is basic as opposed to Advanced obviously suggested by that title.

That's the thing, what I asked was not to "cover to full satisfaction" but to give a short outline, a compact account of the notion of the string. I know what string is in AppleScript and the authors were smart enough to explain that, but in all the tutorials on Unix (applicable to bash shell on the Mac) I watched, their authors simply skip this step as overly obvious (for their taste) and thus redundant (for their taste).


Ok, that basically conforms to my understanding however some clarification needed regarding standard in-/out -put first and foremost:
1. Lines are delimited by using one of those new line characters.
2. Strings are determined by splitting one string of the read data (which to put it simply is an entire output of a read command - in this case standard output) to many subsets/substrings.
3. Any punctuation, whitespace char, save new line/zero, sets new string which is a word (because these delimiters are by default obviuosly).
4. Any other separator also sets a new string.
5. That's interesting for I could see it conversely, based on points 1-4: a string is a superset of lines since a line of characters delimited by an appropriate symbol constructs a string because every non-separated character or/and word is a part of a bigger string item (that could be turned into a substring), especially if reading a text file returns none other than string. No? I'm thinking in terms of stdin and stdout.


Returning to the main topic:

I understand that xargs only passes arguments to another command. What do they mean by replstr and replacement arguments (no more than 5 of replacement arguments if we use -I option without specifying that -R sub option)? What is replaced with what and where? Can I replace certain text items of input? Wouldn't it be wiser to use sed?

I saw even this (read a file which contents are a list of fruits and append a new words (constantly repeating like "I like") to an every line containing a name of a fruit):

Code:

cat fruits.txt | xargs -I {} echo "I like {}"

, where {} is some placeholder (and in maths and AppleScript "{}" actually means a multitude and a list respectively and these two are related notions).

The result (stdout):

I like banana
I like apple
I like pear
..etc (10 more fruit names)

What's the technique? I see that -R is not specified, what does that tell us? "Specify max number of arguments that -I will do replacements in": yeah, but what's the class of a value R takes?


In the way the description is put it's not immediately clear for me how to use these options.

P.S. The first 2 screenshots of xargs man pages as shown in Dash for Mac.