143 lines
2.7 KiB
Markdown
143 lines
2.7 KiB
Markdown
# skip
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Skip part of a file.
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As `head` will show the top of a file up-to a number of line,
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so `skip` will do the opposite, and not show the top of the file,
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but will show the rest.
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Additionally, it can check for whole lines matching,
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or for a token being present on the line.
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N.B.: The `skip` crate used to be an implementation of [Skip list](https://en.wikipedia.org/wiki/Skip_list),
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by [Luo Jia / Zhouqi Jiang](https://github.com/luojia65) ([source](https://github.com/luojia65/skip)).
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## Usage
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### Skip a fixed number of lines
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This example reads the file from stdin.
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```bash
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echo "line 1
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line 2
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line 3
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line 4" > input.txt
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skip 2 < input.txt
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```
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Will output:
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```text
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line 3
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line 4
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```
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### Skip until a number of matching lines
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The whole line must match.
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This example reads the named file.
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```bash
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echo "alpha
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beta
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alpha
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alpha
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gamma
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alpha" > input.txt
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skip 2 --line alpha input.txt
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```
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Will output:
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```text
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alpha
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gamma
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alpha
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```
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### Skip lines until a number of tokens are seen
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Looks for a string within a line, counting each occurance.
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This example reads the file from stdin.
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```bash
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echo "Lorem ipsum dolor sit amet,
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consectetur adipiscing elit,
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sed do eiusmod tempor incididunt
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ut labore et dolore magna aliqua.
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Ut enim ad minim veniam,
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quis nostrud exercitation ullamco
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laboris nisi ut aliquip ex ea
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commodo consequat." > input.txt
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cat input.txt | skip 2 --token dolor
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```
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Will output:
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```text
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Ut enim ad minim veniam,
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quis nostrud exercitation ullamco
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laboris nisi ut aliquip ex ea
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commodo consequat.
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```
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It matches the first `dolor` on line 1,
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and the second on line 4 as part of the word `dolore`.
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### Skip lines until a lines with tokens are seen
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Looks for a string within a line, only counting each matching line once.
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This example reads the file from stdin.
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```bash
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echo "Lorem ipsum dolor sit amet,
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consectetur adipiscing elit,
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sed do eiusmod tempor incididunt
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ut labore et dolore magna aliqua.
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Ut enim ad minim veniam,
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quis nostrud exercitation ullamco
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laboris nisi ut aliquip ex ea
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commodo consequat." > input.txt
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cat input.txt | skip 4 --token m --ignore-extras
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```
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Will output:
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```text
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quis nostrud exercitation ullamco
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laboris nisi ut aliquip ex ea
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commodo consequat.
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```
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Without `--ignore-extras`, it would have found the fourth `m` on line 3.
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```bash
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echo "Lorem ipsum dolor sit amet,
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consectetur adipiscing elit,
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sed do eiusmod tempor incididunt
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ut labore et dolore magna aliqua.
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Ut enim ad minim veniam,
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quis nostrud exercitation ullamco
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laboris nisi ut aliquip ex ea
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commodo consequat." > input.txt
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cat input.txt | skip 4 --token m
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```
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Outputing:
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```text
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ut labore et dolore magna aliqua.
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Ut enim ad minim veniam,
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quis nostrud exercitation ullamco
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laboris nisi ut aliquip ex ea
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commodo consequat.
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```
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