How to print only certain characters?

Question

I have to translate the permissions of a file this way:

r ► c 
w ► s 
x ► e

Then, I must extract the group of characters which are related to owner group. Last step is to print that group of characters without "-" (only letters).

I managed to write a command till now:

student@vm-uso ~team2 $ ls -l partition
-rw-r--r-- 1 student student 10485760 nov 24 21:04 partition
student@vm-uso ~team2 $ ls -l partition | cut -d ' ' -f 1| tr rwx cse | cut -c5-7
c--
student@vm-uso ~team2 $

Forwards, I have to add another '|' in order to print only the letter (without the characters '-').

Answer 1

I think you want this command:

ls -l partition | cut -c5-7 | tr rwx cse |sed 's/-//'

You can remove the one extra command(cut -d ' ' -f 1) and replace it with your last cut command(cut -c5-7) and also add sed 's/-//' at the end to remove all -s. Now you are done. you didn't need to adding extra |.

And even better: you can also change the dash(- character with Null character(\0) as following):

ls -l partition | cut -c5-7 | tr 'rwx-' 'cse\0'

Replaced - char with null character(\0).

Answer 2

Alternative way without ls:

getfacl -c partition | sed -n '/group::/{s/.*:://;y/rwx/cse/;s/-//g;p;}'

Answer 3

Another alternative (piping two tr commands):

ls -l partition | cut -c5-7 | tr -dc rwx | tr rwx cse