Once in a while I need to know what characters are in a file and how often each appears. One reason I might do this is to look for statistical anomalies. Another reason might be to see whether a file has any characters it’s not supposed to have, which is often the case.
A few days ago Fatih Karakurt left an elegant solution to this problem in a comment:
fold -w1 file | sort | uniq -c
fold function breaks the content of a file in to lines 80 characters long by default, but you can specify the line width with the
-w option. Setting that to 1 makes each character its own line. Then
sort prepares the input for
uniq, and the
-c option causes
uniq to display counts.
This works on ASCII files but not Unicode files. For a Unicode file, you might do something like the following Python code.
import collections count = collections.Counter() file = open("myfile", "r", encoding="utf8") for line in file.readlines(): for c in line.strip("\n"): count[ord(c)] += 1 for p in sorted(list(count)): print(chr(p), hex(p), count[p])