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27 lines
845 B
Plaintext
27 lines
845 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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# envsubst
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> Substitutes environment variables with their value in shell format strings.
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> Variables to be replaced should be in either `${var}` or `$var` format.
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> More information: <https://www.gnu.org/software/gettext/manual/html_node/envsubst-Invocation.html>.
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- Replace environment variables in `stdin` and output to `stdout`:
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`echo '{{$HOME}}' | envsubst`
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- Replace environment variables in an input file and output to `stdout`:
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`envsubst < {{path/to/input_file}}`
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- Replace environment variables in an input file and output to a file:
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`envsubst < {{path/to/input_file}} > {{path/to/output_file}}`
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- Replace environment variables in an input file from a space-separated list:
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`envsubst '{{$USER $SHELL $HOME}}' < {{path/to/input_file}}`
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