SHELL

replace first occurence of substring

#To replace the first occurrence of a pattern with a given string,
#use ${parameter/pattern/string}:

#!/bin/bash
firstString="I love Suzi and Marry"
secondString="Sara"
echo "${firstString/Suzi/$secondString}"    

# prints 'I love Sara and Marry'

#To replace all occurrences, use ${parameter//pattern/string}:

message='The secret code is 12345'
echo "${message//[0-9]/X}"           
# prints 'The secret code is XXXXX'


#(This is documented in the Bash Reference Manual, §3.5.3 "Shell Parameter Expansion".)

java replace first occurrence of substring

String payment = "10.20.30.40";
payment = payment.replaceFirst("[.]", ",");  // Replace the first dot (.) with coma (,)
System.out.println(payment);  // 10,20.30.40