One Line Linux Command to Print Out Directory Tree Listing

My professor sent us this little one liner (ok, I had to format it to 2 lines to fit in this blog. You know what I mean) which prints out the current directory tree:

ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' \
-e 's/^/ /' -e 's/-/|/'

What’s going on here?

1
ls -R

– list files and directories recursively
1
grep ":$"

– find lines with : at the end (so only the directories)
1
sed -e

– evaluate expressions on the lines
1
s/:$//

– remove ‘:’ at the end of the line
1
s/[^-][^\/]*\//--/g

– replaces text between / / lines (parent directories) with — , globally on each line
1
s/^/ /

– add space at the beginning of the lines
1
s/-/|/

– replace first – of the line with |

I reduced this using the following command. The most notable difference is that I use find instead of ls, which results in also viewing .hidden directories. I’m not sure which command is faster.

find ./ -type d | sed -e 's/[^-][^\/]*\//--/g;s/--/ |-/'

Both commands result in a formatted directory listing, demonstrated below:

|-sitetransfer
 |---redacteddomain.com
 |-----cache
 |-----templates
 |-------skidoo_too
 |---------images
 |-----------_vti_cnf
 |---------css
 |-----------_vti_cnf
 |---------js
 |-----------scriptaculous
 |-------------src
 |-------------lib
 |---------admin_templates

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