[SOLVED] How to capture one of multiple strings in sed

Issue

I would like to capture multiple strings that occur in any order into a single capture group in sed.

For instance

sed -i '' -E -e "s/(public |static |volatile |transient |final |protected |private )+[[:blank:]]([[:alnum:]])[[:blank:]]([:alnum:]])[[:blank:]]\(([[:alnum:]\,\s]+)\)/\1 func \3\4 -> \2/g"

I have a capture group in () and I have the + sign to signify one or more occurrences, but this syntax creates one or more capture groups whereas I want a single capture group with one or more strings.

I would like sed to greedily capture one or more occurrences of the specified strings in any order into a single capture group.

For instance if I have

private static Object Test (boolean t)
public transient volatile Object Test (int k)

I would like to replace it with

private static Test (boolean t) -> Object
public transient volatile Test(int k) -> Object

As you might guess by now it is a rudimentary sed script that converts some java syntax to swift equivalent.

Solution

You can wrap your initial group into outer group.

In this case \1 will refer to new outer group (as it starts first).

sed -E 's/((public |static |volatile |transient |final |protected |private )+)/\1func /g'

Exmaple of output for your input:

private static func 
public static func 
static transient func 
static volatile func 

Answered By - markalex

Answer Checked By - David Goodson (WPSolving Volunteer)