25 lines
710 B
Markdown
25 lines
710 B
Markdown
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---
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title: Regular Expressions
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TARGET DECK: Obsidian::STEM
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FILE TAGS: linux::cli gawk regexp
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tags:
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- gawk
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---
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## Overview
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Most `awk` patterns are regular expressions delimited with `/`. We can use `~` and `!~` to perform more complicated regexp filtering:
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```bash
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# Matches any line with `li` somewhere.
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$ awk '/li/' data
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$ awk `$0 ~ /li/` data
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# Matches any line with `li` somewhere in the first field.
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$ awk '$1 ~ /li/' data
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```
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`awk`'s implementation of regexps are a superset of [[posix/regexp|POSIX EREs]].
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## References
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* Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
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