Bash: how to take a number from a string? (possibly regex)

Question

I want to get the number of characters in a file.

wc -c f1.txt | grep [0-9]

But this code returns the string where grep found the numbers. I want to get only 38 . How?

+3

micobg May 07, '12 at 17:42

2 answers

transfer data to wcfrom stdin instead of file:nchars=$(wc -c < f1.txt)

+5

glenn jackman May 07, '12 at 17:56

anubhava · Accepted Answer · 2012-05-07T17:45:14+0000

You can use awk:

wc -c f1.txt | awk '{print $1}'

OR using grep -o:

wc -c f1.txt | grep -o "[0-9]\+"

OR using bash regex features:

re="^ *([0-9]+)" && [[ "$(wc -c f1.txt)" =~ $re ]] && echo "${BASH_REMATCH[1]}"