implement bash filter

[ldgabbay]

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[ldgabbay]

• bash — As per the bash manual,

Enclosing characters in double quotes (‘"’) preserves the literal value of all characters within the quotes, with the exception of ‘$’, ‘`’, ‘\’, and, when history expansion is enabled, ‘!’. 

The characters ‘$’ and ‘`’ retain their special meaning within double quotes (see Shell Expansions). 

$
`
\$          $
\`          `
\"          "
\\          \
\newline    continuation

The backslash retains its special meaning only when followed by one of the following characters: ‘$’, ‘`’, ‘"’, ‘\’, or newline. Within double quotes, backslashes that are followed by one of these characters are removed. Backslashes preceding characters without a special meaning are left unmodified. A double quote may be quoted within double quotes by preceding it with a backslash. If enabled, history expansion will be performed unless an ‘!’ appearing in double quotes is escaped using a backslash. The backslash preceding the ‘!’ is not removed.

The special parameters ‘*’ and ‘@’ have special meaning when in double quotes (see Shell Parameter Expansion).