Etydhv

The following code provides a backwards output when inputted as first to last, so input is required to be in reverse. How can this be flipped/reversed?

EDITED on 2019-05-23_07:52:04

(printf 'g?%s?m0n' 0005 0004 0003 0002 0001 ; printf 'wqn') | ed -s file.txt

However, I would like to do:

(printf 'g?%s?m0n' 0001 0002 0003 0004 0005 ; printf 'wqn') | ed -s file.txt

and get output order at the top of file.txt like this:

0001
0002
0003
0004
0005

file.txt is a playlist for ffmpeg and the zero padded numbers above are some chosen filenames of videos. The playlist has a bunch of filenames/videos already in it and I'd like to move a few to the top before compiling. However, not be required to input them in reverse order like the printf command requires if first to last ordering is desired.

UPDATED on 2019-05-23_07:54:27

$ cat file.txt
5575
3585
0004
7774
0003
5385
0001
8658
0002
0005

$ (printf 'g?%s?m0n' 0001 0002 0003 0004 0005 ; printf 'wqn') | ed -s file.txt

$ cat file.txt
0005
0004
0003
0002
0001
9374
4845
4834
4883
5848

Take note of the last cat command and the ordering of the output.

( printf 'g?%s?m0n' 0005 0004 0003 0002 0001 | tac ; printf 'wqn' ) | ed -s file.txt

This reverses the ed commands produced by the first printf.

Even though my suggestion with tac worked, I think that maybe, your are making this much harder than it is.

If you have file.txt, and you simply want to add some lines at the beginning of file.txt, say, lines you have in a header_file.txt, you can simply do this:

cat header_file.txt file.txt > new_playlist.txt

and done.

Instead of moving lines on-by-one to the top, you could move the one-by-one to the bottom (which preserves the desired order) and then move them as a group to the top. Taking it a step at a time:

1. 
   

   Insert a placeholder line (whose contents could be anything - the simplest is just an empty line) and then move the selected lines to the end of the file m$. (NOTE: I changed the g?...? reverse search to more conventional g/.../ - it doesn't actually matter which direction you search in.)

   
   
   

   $ printf '$ann.n'; printf 'g/%s/m$n' 0001 0002 0003 0004 0005; printf ',pnqn'; | ed -s file.txt
   5575
   3585
   7774
   5385
   8658
   
   0001
   0002
   0003
   0004
   0005
   

   
   


2. 
   

   Now add a mark (kx) on the placeholder line, so that we can address lines x to $ and move them to the top using 'x,$m0:

   
   
   

   $ printf '$ann.nkxn'; printf 'g/%s/m$n' 0001 0002 0003 0004 0005; printf ''x,$m0n,pnqn'; | ed -s file.txt
   
   0001
   0002
   0003
   0004
   0005
   5575
   3585
   7774
   5385
   8658
   

   
   


3. 
   

   Finally we need to remove the placeholder (which is now line 1):

   
   
   

   $ printf '$ann.nkxn'; printf 'g/%s/m$n' 0001 0002 0003 0004 0005; printf ''x,$m0n1dn,pnqn'; | ed -s file.txt
   0001
   0002
   0003
   0004
   0005
   5575
   3585
   7774
   5385
   8658
   

   
   

Putting it all together and replacing ,p by wq to edit in place:

$ cat file.txt
5575
3585
0004
7774
0003
5385
0001
8658
0002
0005
$
$ printf '$ann.nkxn'; printf 'g/%s/m$n' 0001 0002 0003 0004 0005; printf ''x,$m0n1dn,wqn'; | ed -s file.txt
$
$ cat file.txt
0001
0002
0003
0004
0005
5575
3585
7774
5385
8658