Hi,

I want to remove the first line from a flat file using unix command as simple as possible. Can anybody give me a hand ?

Thanks in advance.

xli

printf ":1d\n:wq\n" | ex name_of_your_flatfile

another way,

sed -i '1d' filename

That does not remove the line from the file, is streams the file to stdout with the first line removed. It would need to be redirected into a temporary file and moved back to replace the original file.

Also if I am correct, and I remember correctly the flatfile xli is talking about is pretty huge (millions of lines), and do it that way could be pretty slow.

thanks for the explanation. i give another reply

perl -pi -e '$_ = "" if ($. == 1);' filename

which one is fastest?

Not always - it depends on which version of sed you're using.... GNU sed supports the -i option to edit files in place (a backup extension can also be supplied much like perls -i option).

Observe...

$ cat > flatfile
1st line
2nd line
3rd line
^D
$ sed -i '1d' flatfile
$ more flatfile
2nd line
3rd line

perl -pi -e '$_ = "" if ($. == 1);' filename

works very well.

Thanks very much for your help, Tanku and Reborg.

Regards, xli