Search for text between two patterns with multiple lines in between

Question

I have a simple question. I have a file containing:

more random text

*foo*
there
is 
random
text
here
*foo*

foo
even
more
random
text
here
foo
more random text         


        

Answer 1

With sed:

$ sed -n '/foo/{:a;n;/foo/q;p;ba}' infile
there
is
random
text
here

Explained:

/foo/ {     # If we match "foo"
    :a      # Label to branch to
    n       # Discard current line, read next line (does not print because of -n)
    /foo/q  # If we match the closing "foo", then quit
    p       # Print line (is a line between two "foo"s)
    ba      # Branch to :a
}

Some seds complain about braces in one-liners; in those cases, this should work:

sed -n '/foo/ {
    :a
    n
    /foo/q
    p
    ba
}' infile

Answer 2

Since checking for "foo" (using /foo/) is relatively expensive, the following avoids that check and will work with all awks worthy of the name:

awk 'c==2 {next} /foo/{++c;next} c==1' file

Answer 3

$ awk '/foo/{++c;next} c==1' file
there
is
random
text
here

$ awk '/foo/{++c;next} c==3' file
even
more
random
text
here

or with GNU awk for multi-char RS you COULD do:

$ awk -v RS='(^|\n)[^\n]*foo[^\n]*(\n|$)' 'NR==2' file
there
is
random
text
here

$ awk -v RS='(^|\n)[^\n]*foo[^\n]*(\n|$)' 'NR==4' file
even
more
random
text
here

See https://stackoverflow.com/a/17914105/1745001 for other ways of printing after a condition is true.