Append string to first line of a file

Hi,

Please suggest me to write unix command, HEADER20110101 string append to first line of a file..

Regards
Akshu

i am adding 123 in the first line of the file called test

 
 
$ nawk ' { if (NR==1){printf("123%s\n",$0)} else {print} }' test 
123abc
abc
abc
abc
abc

$ cat test
abc
abc
abc
abc
abc

---------- Post updated at 11:50 AM ---------- Previous update was at 11:48 AM ----------

using sed

 
$ sed ' 1 s/.*/123&/' test
123abc
abc
abc
abc
abc

Alternate awk..

awk 'NR==1{$0="header\n"$0}1' inputfile

Hi,

Try this:

sed -i '1s/.*/ HEADER20110101&/' a.txt