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38 lines
968 B
Plaintext
38 lines
968 B
Plaintext
---
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syntax: markdown
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tags: [tldr, common]
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source: https://github.com/tldr-pages/tldr.git
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---
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# expr
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> Evaluate expressions and manipulate strings.
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> More information: <https://www.gnu.org/software/coreutils/expr>.
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- Get the length of a specific string:
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`expr length "{{string}}"`
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- Get the substring of a string with a specific length:
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`expr substr "{{string}}" {{from}} {{length}}`
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- Match a specific substring against an anchored pattern:
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`expr match "{{string}}" '{{pattern}}'`
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- Get the first char position from a specific set in a string:
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`expr index "{{string}}" "{{chars}}"`
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- Calculate a specific mathematic expression:
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`expr {{expression1}} {{+|-|*|/|%}} {{expression2}}`
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- Get the first expression if its value is non-zero and not null otherwise get the second one:
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`expr {{expression1}} \| {{expression2}}`
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- Get the first expression if both expressions are non-zero and not null otherwise get zero:
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`expr {{expression1}} \& {{expression2}}`
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