How to add a header and/or footer to a sed or awk stream?

This can be done in sed with

sed -e $'1i\\\nSTART' -e $'$a\\\nEND' 

1i means insert before line 1; $a means append after the last line.  The $'…' syntax is bash-specific.  In other shells, you should be able to do this with:

sed -e '1i\Enter START' -e '$a\Enter END'Enter

Warning: the question says “I have a bunch of output ...”  If you run the above command with no data, you will get no output, because the command depends on there actually being a first line and a last line.  The other two answers will give the header and footer even if the input is null.

If you're already using sed, you can use 1 to match the first line and $ to match the last line (see Scott's answer). If you're already using awk, you can use a BEGIN block to run code before the first line and an END block to run code after the last line (see Michael Durrant's answer).

If all you need to do is add a header and a footer, just use echo and cat.

echo START cat echo END 

In a pipeline, to run multiple commands, use { … } to tell the parser that they're one single compound command.

content-generator | { echo START; cat; echo END; } | postprocessor 

sed -e '1s/.*/START\n&/g' -e '$s/.*/&\nEND/g' filename START All this code on all these lines and all these END 

Python

#!/usr/bin/python k=open('filename','r') o=k.readlines() for i in range(0,len(o),1): if ( i == 0 ): print "START" print o[i].strip() elif ( i == (len(o)-1)): print o[i].strip() print "END" else: print o[i].strip() 

output

START All this code on all these lines and all these END