count number of words and lines from stdin

Question

How can i write a program using STANDARD UNIX UTILITIES that will read data from standard input one character at a time and out the results to standard output. I know that it runs similar to what a C program in this case. I was told that this could be done in one line of code but never done Unix Pipeline Programming so i am just curious. The purpose of the program is to read data from standard input and count the number of words an lines and out in standard output the total number of words and lines

I came up with the following code but i am unsure:

tr A-Z a-z < file | tr -sc a-z | sort uniq -c wc '\n'

Any thoughts or suggestions on how i can get what i want?

results of what? Your question is not clear about what your program needs to actually do. — Celada, Dec 03 '12 at 21:19
can you provide a sample input file and the expected output? — nullrevolution, Dec 03 '12 at 22:30
Your code has some syntax errors (missing `|` characters between `sort` and `uniq` and between `uniq -c` and `wc`), but it also does a lot more than your question is asking for. If all you want is the number of words and lines, just do `wc -wl file`. — Mark Reed, Dec 03 '12 at 22:31
Okay thank you, if i were to change my code, it would be as such: `tr A-Z a-z wc -wl < file | tr -sc a-z | sort | uniq -c | -w | -l | '\n'` ? — user1832605, Dec 04 '12 at 00:34

Chris Seymour · Accepted Answer · 2012-12-03T22:26:36.063

11

You use wc (word count) with the -w option to count words in a file or -l for lines.

$ cat file.txt
this file has 5 words.

$ wc -w file.txt             # Print number of words in file.txt
5 file.txt

$ wc -l file.txt             # Print number of lines in file.txt
1 file.txt

$ wc file.txt                # No option, print line, words, chars in file.txt
 1  5 23 file.txt

Other options to wc:

  -c, --bytes            print the byte counts
  -m, --chars            print the character counts
  -l, --lines            print the newline counts
  -L, --max-line-length  print the length of the longest line

edited Dec 03 '12 at 22:26

answered Dec 03 '12 at 22:04

Chris Seymour

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You can also read from stdin (no file involved) with: | wc -l – Victor Basso Jan 31 '15 at 15:15
Why am I facing the number 4 while doing `echo foo | wc -m`? I'd expect 3. Is there any non-visible character like '\n or smth. like that? – Arthur Eirich Apr 02 '19 at 11:59
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@ArthurEirich yes, use `-n` if you don't want the newline character `echo -n foo | wc -m` – Chris Seymour Apr 02 '19 at 12:36

count number of words and lines from stdin

1 Answers1