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48 lines
1.4 KiB
Markdown
48 lines
1.4 KiB
Markdown
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# Word splitting
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FIXME to be continued!
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Word splitting occurs once any of the following expansions are done (and
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only then!)
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- [Parameter expansion](/syntax/pe)
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- [Command substitution](/syntax/expansion/cmdsubst)
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- [Arithmetic expansion](/syntax/expansion/arith)
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Bash will scan the results of these expansions for special `IFS`
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characters that mark word boundaries. This is only done on results that
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are **not double-quoted**!
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## Internal Field Separator IFS
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The `IFS` variable holds the characters that Bash sees as word
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boundaries in this step. The default contains the characters
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- \<space\>
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- \<tab\>
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- \<newline\>
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These characters are also assumed when IFS is **unset**. When `IFS` is
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**empty** (nullstring), no word splitting is performed at all.
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## Behaviour
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The results of the expansions mentioned above are scanned for
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`IFS`-characters. If **one or more** (in a sequence) of them is found,
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the expansion result is split at these positions into multiple words.
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This doesn't happen when the expansion results were **double-quoted**.
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When a null-string (e.g., something that before expanded to
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\>\>nothing\<\<) is found, it is removed, unless it is quoted (`''` or
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`""`).
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<u>**Again note:**</u> Without any expansion beforehand, Bash won't
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perform word splitting! In this case, the initial token parsing is
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solely responsible.
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## See also
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- [Introduction to expansion and substitution](/syntax/expansion/intro)
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- [Quoting and escaping](/syntax/quoting)
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