Issue
I'm trying to become familiar with sed by extracting email address from input in the following form:
something_from.someone:[email protected]
That is the input I'm sending to sed, I'm trying to remove everything up to and including ::
sed 'd/[[alphanum:]]+[.][[:alphanum:]]+[:]//'
Based on my research, this should do it, but I'm getting this error:
sed: 1: "d/[[:alphanum:]]+[.][[: ...": extra characters at the end of d command
Any ideas as to what I'm doing incorrectly?
Solution
Your delete syntax is incorrect. To delete in sed you need to do:
sed '(separator) [pattern to delete](separator)d'
Thus, for example:
sed -e '/regex/d' infile
This is for deleting whole lines generally. What you want to do instead is keep some part of the line so you need a capture-and-replace:
sed -e 's/regex-to-drop\(regex-to-keep\)/\1/g' input-file
The 's' is for substitute and the 'g' is for global, and the \( \) is what is captured while the \1 is where I want the captured thing to go. If I had a series of captured items,
\(something\)\(something_else\)
I could reproduce them with another character between them by simply putting the following in the substitute part of the sed command:
\1 ;; \2
This would produce: something ;; something_else and altogether would look like:
sed -e 's/\(something\)\(something_else\)/\1 ;; \2/g' input-file
In your case, it looks like you want to drop everything before the colon:
sed -e 's/^.*:\(.*\)$/\1/g' input-file
Footnote to the above as suggested by @fedorqui:
Sed uses standard regex notation to refer to the beginning and end of a line, so "^" refers to the beginning of the line and "$" refers to the end of the line. Thus, the complete explanation of the above is as follows:
's/^.*:
Everything from the start of the line up to the colon (the "s" means we're setting up a 'substitute' command).
Then:
\(.*\)$/
CAPTURE everything up to the end of the line, and
/\1/g'
Substitute the WHOLE line with the captured item. Do it globally (for the whole file).
Answered By - erewok Answer Checked By - Mildred Charles (WPSolving Admin)