[DOC] Doc for field processing #10008
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Converted to Draft (temporarily) -- there's a little more that can be done here. |
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Ready for review (option |
doc/command_line/field_processing.md
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| Note that `gets` reads the next line and sets global variable `$_` | ||
| to the last read line; | ||
| note also that character `'$'` must be escaped as `'\$'`: |
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That escape is needed when enclosed in double quotes or no quotes.
Is it for the sake of Windows, not to use single quotes?
doc/command_line/field_processing.md
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| Option `-F`, when given with option `-a`, | ||
| specifies that its argument is to be the input field separator to be used for splitting: | ||
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| ```sh | ||
| $ ruby -an -Fs -e "p \$F" desiderata.txt | ||
| ["Go placidly amid the noi", "e and the ha", "te,\n"] | ||
| ["and remember what peace there may be in ", "ilence.\n"] | ||
| ["A", " far a", " po", "", "ible, without ", "urrender,\n"] | ||
| ["be on good term", " with all per", "on", ".\n"] | ||
| ``` |
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I think it's worth mentioning that the arguments are compiled as regular expressions.
$ ruby -an -F'[.,]\s*' -e 'p $F' desiderata.txt
["Go placidly amid the noise and the haste"]
["and remember what peace there may be in silence"]
["As far as possible", "without surrender"]
["be on good terms with all persons"]There was a problem hiding this comment.
Added @nobu example with remark.
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Changed heading levels (downward), with a view to possible eventual file inclusion. |
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@peterzhu2118, is this ready to merge, do you think? |
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Can you also clarify how this doc will be used? For example, where will it be linked from. Right now, it's not very easy to find by the average reader. |
I'm working toward docs in I'd like then to add a URL address to the help text, referring the reader to these robust write-ups. (Too bad it can't be a link -- or can it?) |
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@peterzhu2118, ready, I think. |
Documents command-line options
-n,-p,-a, and-F, each affecting field processing.I've put the new file into directory
doc/command_line/(instead ofdoc/) because I'm planning more files documenting more CLI options. These may eventually be gathered into an inclusivedoc/command_line_options.md.