How to make sed remove everything else except an email address.

Question

how do I get "sed" to delete everything else except an email address.

db dump: someusername ::: kRW...0fPc ::: $2a$10$...aucvkDt86 ::: [e-mail]

Answer 1

Is there any need to do this? How about grep? Here's how to use it with the regex that you specified:

$ cat dbdump.txt 
db dump: someusername ::: kRW...0fPc ::: $2a$10$...aucvkDt86 ::: [e-mail]
another line with two e-mail addresses <[e-mail]> on it -- [e-mail]

$ grep -EiEio '\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\b' dbdump.txt
[e-mail]
[e-mail]
[e-mail]

The flag -oprints only the relevant parts, i.e. email addresses only. -imakes a matching case insensitive. It even finds multiple email addresses on one line.

Edit: I could not resist -EiEio. I believe that grep -Eio, or egrep -iowill work too ...

Answer 2

sed:

$ echo "db dump: someusername ::: kRW...0fPc ::: $2a$10$...aucvkDt86 ::: [e-mail]"|sed 's/.*::: //' [e-mail] 

awk:

$ echo "db dump: someusername ::: kRW...0fPc ::: $2a$10$...aucvkDt86 ::: [e-mail]"|awk '{print $NF}'

EDIT: - , , - . :

• http://en.wikipedia.org/wiki/Email_address

, , , 1$%3{C}@example.com - ( ). ( John [e-mail]). , , .

, , , , @, :

cat your-file.txt|grep @

. - :

$ echo "garbage [e-mail] garbage"|sed 's/[^@]* \([a-zA-Z0-9.]*@[^ ]*\).*/\1/'
[e-mail]

, :

• .
• ( , )
• local-part ( @) ( ),

([a-zA-Z0-9.]), - . [a-zA-Z0-9.-_], - _.

Answer 3

, , . , , . , .

sed 's/^.* \([^@ ]\+@[^ ]\+\) \?.*$/\1/'

$ cat dbdump
this line with no valid @ email address is untouched
::: a0$...aucvkDt86 ::: [e-mail]
::: a0$... [e-mail] db dump: someusername :::

$  sed 's/^.* \([^@ ]\+@[^ ]\+\) \?.*$/\1/' ./dbdump
this line with no valid @ email address is untouched
[e-mail]
[e-mail]

Answer 4

GNU sed:

sed -r 's/\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}/\n&\n/ig;s/(^|\n)[^@]*(\n|$)/\n/g;s/^\n|\n$//g;/^$/d' inputfile

• separate input lines so that email addresses and other lines are separated by newlines
• erase sequences that consist only of non-characters separated by newlines or the beginning or end of an input line
• erase extra lines and empty lines