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.
project/assets/70137592/402938/* <e.g. all the files of a type> I have been assured the schema and numeric sort order of subdirectories within '70137592' will never change. :shrug: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 (i.e. one line).
You could do something like a
ls meals/dinner | head -n 1
to extract the first line.
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