Oneliner ---split string to character by piping shell output to perl

Shell Programming and Scripting
1

Hello,
I was trying to split a string to characters by perl oneliner.

echo "The quick brown fox jumps over the lazy dog" | perl -e 'split // '

But did not work as with bash script pipe:

echo "The quick brown fox jumps over the lazy dog" | fold -w1 | sort | uniq  -ic 

      8  
      1 T
      1 a
      1 b
      1 c
      1 d
      3 e
      1 f
      1 g
      2 h
      1 i
      1 j
      1 k
      1 l
      1 m
      1 n
      4 o
      1 p
      1 q
      2 r
      1 s
      1 t
      2 u
      1 v
      1 w
      1 x
      1 y
      1 z

However, I want ignore the space and case.
1) What did I miss with my perl oneliner?
2) What are the options to ignore the space and case?
3) Want perl oneliner for learning purpose for 2)
Googled for a while, but no example for my exact case. Thanks a lot!

2

The following code:

echo 'The quick brown fox jumps over the lazy dog' | perl -le 'print join "$/", grep /\S/, split //,<>'

produces:

T
h
e
q
u
i
c
k
b
r
o
w
n
f
o
x
j
u
m
p
s
o
v
e
r
t
h
e
l
a
z
y
d
o
g

Could you clarify what exactly do you mean by "ignore the case"?

3

I meant to combine upper case and lower case letters. In this example only T and t are redundant. So that letter "t" appears 2 times, not 1 for each. Thanks!

4 
echo 'The quick brown fox jumps over the lazy dog' | 
  perl -le 'print join "$/", grep /\S/ && !$_{"\L$_"}++, split //, <>
    '
5

If you need the number of occurrences:

echo 'The quick brown fox jumps over the lazy dog' | 
  perl -le '/\S/ and $l{$_} = ++$cnt{"\L$_"} for split //, <>;
  END {
    print $cnt{"\L$_"}, " ", $_
      for keys %l;
    }'

Do you need to preserve the original order?

6

Thanks roudlov!
There is small bug where "T" and "t" were both counted 2 times. Actually only "t" is needed as "T" should be counted as "t". Anyway, "split //, <>" played the trick for my case. I can pipe the output with sort | unique to get the count:

echo 'The quick brown fox jumps over the lazy dog' | perl -le 'print join "$/", grep /\S/, split //, <>' | tr '[:upper:]' '[:lower:]' | sort | uniq -c

By the way, do you have a good resource to learn perl oneliner? Thanks again!

7

All in Perl:

echo 'The quick brown fox jumps over the lazy dog' | 
  perl -le '/\S/ and $cnt{"\L$_"}++ for split //, <>;
  END {
    print "$cnt{$_} $_"
      for sort keys %cnt;
    }'

If I understand correctly what you mean by "perl oneliner",
I would suggest Effective Perl Programming: Ways to Write Better, More Idiomatic Perl (2nd Edition).

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