Hi!

I want to format this file using unix commande sed or else
>
> 1505
> 1506
So that it looks like
>1505
>1506

Thanks for your help

it's not clear in the post but my file contain a first blank line that i manage to delete thanks to sed "1d"
But after that the number are precieded by a blank too this way
blankblankblank1505
blankblankblank1506

How can i delete the blank in the second,the third and so one in the file to format the file like
1505
1506
1507
...

See man sed for an explanation on option s/regexp/replacement
You can look up man grep for help on regular expressions too.

Cheers

You can remove all blank lines from a file (say sample_file.txt) by doing :

sed '/^$/d' sample_file.txt

Hope this is what you needed