bash – 用$@参数支持扩展

command "${@/#/foo}" "${@/#/bar}"

这使用shell parameter expansion的替换变体.#将匹配锚定到参数的开头.

$set -- a abc xyz
$echo command "${@/#/foo}" "${@/#/bar}"
command fooa fooabc fooxyz bara barabc barxyz
$

Is there a way to scale this for larger {foo,bar,baz,...}$@ or {foo,bar}{123,456}$@?

是的,但你最终会使用数组：

$set -- a abc xyz
$args=( "$@" )
$for prefix in foo bar baz who why; do prefixed1+=( "${args[@]/#/$prefix}" ); done
$echo command "${prefixed1[@]}"
command fooa fooabc fooxyz bara barabc barxyz baza bazabc bazxyz whoa whoabc whoxyz whya whyabc whyxyz
$

或者(注意你必须正确排序)：

$for prefix in 123 456; do prefixed1+=( "${args[@]/#/$prefix}" ); done
$for prefix in foo bar; do prefixed2+=( "${prefixed1[@]/#/$prefix}" ); done
$echo command "${prefixed2[@]}"
command foo123a foo123abc foo123xyz foo456a foo456abc foo456xyz bar123a bar123abc bar123xyz bar456a bar456abc bar456xyz
$

请注意,这会保留参数中的空格：

$unset prefixed1 prefixed2
$set -- 'a b' 'x y z'
$args=( "$@" )
$for prefix in 'p p-' '123 456 '; do prefixed1+=( "${args[@]/#/$prefix}" ); done
$echo command "${prefixed1[@]}"
command p p-a b p p-x y z 123 456 a b 123 456 x y z
$for prefix in 'foo 1-' 'bar 2-'; do prefixed2+=( "${prefixed1[@]/#/$prefix}" ); done
$echo command "${prefixed2[@]}"
command foo 1-p p-a b foo 1-p p-x y z foo 1-123 456 a b foo 1-123 456 x y z bar 2-p p-a b bar 2-p p-x y z bar 2-123 456 a b bar 2-123 456 x y z
$printf "[%s]n" "${prefixed2[@]}"
[foo 1-p p-a b]
[foo 1-p p-x y z]
[foo 1-123 456 a b]
[foo 1-123 456 x y z]
[bar 2-p p-a b]
[bar 2-p p-x y z]
[bar 2-123 456 a b]
[bar 2-123 456 x y z]
$

第一个循环可能是：

for prefix in 'p p-' '123 456 '; do prefixed1+=( "${@/#/$prefix}" ); done

不使用${args [@]}数组.