UNIX for Dummies Questions & Answers

Hi i have a problem how to put som lines on top or in the bottom of the text with sed.

problem is that i am reading from stdin and when i have som lines starting with ++, i have to put some characters on the top of the lines starting with that ++

example of input

oooo
++abcd
++befg
++def
++and
++quit
ooo

output:

oooo
<start>
++abcd
++befg
++def
++and
++quit
<end>
oooo

can anyone expirienced help me ? the problem is that sed is allways using only one line , i saw some commands to sed ,that it saves another lines in to the buffer but i didnt know how to write it . thx for answer

Rather than using sed, I suggest you consider using awk. The following awk script works for the sample input you provided.

Code:

BEGIN { state=0 }
{
   if (substr($0,1,2) == "++" ) {
      if (state == 0) {
          state=1
          print "<start>"
      }
   } else {
      if ( state == 1 ) {
          state=0
          print "<end>"
      }
   }
   print $0
}