Question

I’m looking for a Linux/UNIX command that will determine the distinct characters in a file. Character counts would be nice, but not essential. For example, if I run the command on a file containing this data…

This is
my data
file.

…it would give me this as output…

T h i s m y d a t f l e .

…or even better, this.

T:1 h:1 i:3 s:2 m:1 y:1 d:1 a:2 t:1 f:1 l:1 e:1 .:1

In the output, the order of the characters doesn’t matter, nor does it matter whether they are separated by spaces, tabs, lines, etc.

Answer 1

To print unique characters:

$ grep -o . file | sort -u | tr -d '\n'
 .Tadefhilmsty

To count the number of occurrences of each character:

$ grep -o . file | sort | uniq -c
      2
      1 .
      1 T
      2 a
      1 d
      1 e
      1 f
      1 h
      3 i
      1 l
      1 m
      2 s
      1 t
      1 y

I’ll leave the formatting to you.