How to reverse the output of the grep command?

Question

i have one problem with grep command. in my called script i use:

   "ServicePassword":fooooooooooo
   "ServiceUserName":barrrrrrrrr
grep -E '"ServiceUserName"|"ServicePassword"' >> user.txt

but in user.txt file i will get first "ServicePassword":fooooooooooo then "ServiceUserName":barrrrrrrrr How can i use grep command to reverse it to get first ServiceUserName then ServicePassword output in user.txt file ? I need it only this sequence. i try to change:

grep -E '""ServicePassword""|"ServiceUserName"' >> user.txt

and nothing.... maybe exist a better solution?

Solution 1

grep just filters, man grep : print lines matching a pattern, to change order another tool must be used, as there's only two items maybe adding |sort or |sort -r (sort reverse) can help.

grep -E '"ServiceUserName"|"ServicePassword"' | sort -r >> user.txt

Solution 2

You can use and adapt the tac command below:

$ cat test.txt
"ServicePassword":fooooooooooo
"ServiceUserName":barrrrrrrrr

$ egrep '"ServicePassword"|"ServiceUserName"' test.txt | tac
"ServiceUserName":barrrrrrrrr
"ServicePassword":fooooooooooo