using cut command in bash [duplicate]

Question

This question already has answers here:

get just the integer from wc in bash (19 answers)

Closed 8 years ago.

I want to get only the number of lines in a file: so I do:

$wc -l countlines.py 
   9 countlines.py

I do not want the filename, so I tried

$wc -l countlines.py | cut -d ' ' -f1

but this just echo empty line.

I just want number 9 to be printed

Answer 1

Use stdin and you won't have issue with wc printing filename

wc -l < countlines.py

Answer 2

You can also use awk to count lines. (reference)

awk 'END { print NR }' countlines.py

• where countlines.py is the file you want to count

Answer 3

If your file doesn't ends with a \n (new line) the wc -l gives a wrong result. Try it with the next simulated example:

echo "line1"    >  testfile #correct line with a \n at the end
echo -n "line2" >> testfile #added another line - but without the \n

the

$ wc -l < testfile
       1

returns 1. (The wc counts the number of newlines (\n) in a file.)

Therefore, for counting lines (and not the \n characters) in a file, you should to use

grep -c '' testfile

e.g. find empty character in a file (this is true for every line) and count the occurences -c. For the above testfile it returns the correct 2.

Additionally, if you want count the non-empty lines, you can do it with

grep -c '.' file

Don't trust wc :)

Ps: one of the strangest use of wc is

grep 'pattern' file | wc -l

instead of

grep -c 'pattern' file

Answer 4

cut is being confused by the leading whitespace.

I'd use awk to print the 1st field here:

% wc -l countlines.py | awk '{ print $1 }'

Answer 5

As an alternative, wc won't print the file name if it is being piped input from stdin

$ cat countlines.py | wc -l
9

Answer 6

yet another way :

cnt=$(wc -l < countlines.py )
echo "total is $cnt "

Answer 7

Piping the file name into wc removes it from the output, then translate away the whitespace:

wc -l <countlines.py |tr -d ' '

Answer 8

Use awk like this:

wc -l countlines.py | awk {'print $1'}