Count number of characters per listed filename

Question

Given the following ls result:

$ ls
Desktop  Documents  Downloads  Music  Pictures  Public  Templates  Videos

This will give the total number of characters for all files:

$ ls | wc -m
67

But how can I have calculate the number of characters per file name? For the same file list the result I'm after would be something like this:

8
10
10
6
etc...

Answer 1

This can be done in a very simple shell script:

for file in *; do echo -n "$file" | wc -m; done

Just loop through each file echoing the name to wc. The -n on the echo is so that it doesn't append a newline, which would erroneously increase the count by 1.

Answer 2

You don't need to call out to wc, bash is perfectly capable: ${#var} is the length of the value of $var.

for f in *; do echo ${#f}; done

reference

Answer 3

While @Patrick's answer is perfectly fine if you have to do a similar task over a directory tree's worth of files you'll need to change your tactics slightly. One method for handling this is to use find & while.

find & while

$ depth=2
$ find . -maxdepth $depth -type f -print0 | sed 's|\./||g' | \
    while IFS= read -r -d '' file; do \
      f=$(basename "$file"); printf "%s: %s\n" "$file" "${#f}"; \
    done | column -s : -t
dir2/more files3.txt        15
some long spacey file.txt   25
dir1/more files1.txt        15
dir1/more files2.txt        15
file 1.txt                  10
file 2.txt                  10

The above will generate a list of files separated by \0 (i.e. NULLs). You can use the variable $depth to control how deep find will look. This list is then scrubbed so that any .\ characters are removed via sed.

Lastly we loop through this list and use a printf to print each file's name out along with its length, using Bash's built-in facility to count the length of a string, ${#var}. The printf will print the file + its path but only the size of the file.

The column -s : -t is just to pretty print it. It does so by splitting the output on the colon, :, and then splitting the output up into equidistant columns.