How do I split a linefeed delimited string in awk and use its output on the same command line in bash?

Question

I have a two part problem using awk in bash , first to properly split linefeed delimited text, and second to use the output of awk in the same command line.

For the sake of an example, I would like to list the contents of the second subdirectory within a specific subdirectory.

Assume my directory structure is something like this:

$HOME/meals/dinner
           /dinner/appetizer
           /dinner/dish

I used the command below which returned text delimited by and ending in 0x0A

$ ls meals/dinner | awk '{split($0,a,"\\\\n"); print a[1]; }'
appetizer
dish

xxd output shows (00000000: 6170 7065 7469 7a65 720a 6469 7368 0a appetizer.dish.)

As a test, I tried this, and it worked.

$ echo "AAA\nBBB" | awk '{split($0,a,"\\\\n"); print a[1]}'
AAA
$ echo "AAA\nBBB" | awk '{split($0,a,"\\\\n"); print a[2]}'
BBB

What is my split doing incorrectly with the output of ls?

Second problem : Even if I extract the delimited directory name, I am not sure how to use it as part of a subsequently executed command on the same command line.

As a simple test, I request an example to ls the extracted directory by name.

Thank you.

Update: I have a workaround, though not exemplary. Here # is the index of a specific subdirectory within an ordered list of subdirectories.

find directory/. -maxdepth 1 -mindepth 1 -type d -printf '%f\n' | head -n # | tail -n 1

However, @EdMorton has pointed out that *nix filenames allow linefeeds. For my purposes, the filenames are generated by a tool and won't have linefeeds but I would be thrilled to have a better solution.

Also, it became clear that my use of echo generated a false positive, and that my assumption that awk was treating \n as an escape sequence was faulty.

A few commentors have asked what I am trying to do. Apologies that my original post was not clear.

I want to get a single-depth list of subdirectory names within a known directory, I want to get the name of the Nth subdirectory based on my script needs, and I want to use that subdirectory name (ideally) in the same command line to process the contents of that subdirectory.

• the name of the main directory is the same as its project
• there is a known subdirector, say "assets", containing an unknown number of subdirectories, each named uniquely based on a number unique to the system, like a GUID but not.
• within each uniquely named subdirectory of "assets" exists uniquely named and ordered based, but the subdirectory names (for reasons known only to the tool creator) are unknown - just that they are ordered partly by type, partly by a unique number.
• the Nth subdirectory in any main directory will always contain a certain file type
• Example: project/assets/70137592/402938/* <eg all the files of a type> I have been assured the schema and numeric sort order of subdirectories within '70137592' will never change. :shrug:

Answer 1

You are splitting by a literal backslash, followed by the letter n . BTW, your echo command does not output a newline, as you can verify easily by

echo "AAA\nBBB"  | wc -l

which outputs 1 (ie one line).

You could do something like a

ls meals/dinner | head -n 1

to extract the first line.