Bash: how to take a number from string? (regular expression maybe)

Question

I want to get a count of symbols in a file. ``` wc -c f1.txt | grep [0-9] ``` But this code return a line where grep found numbers. I want to retrun only 38. How?

Accepted Answer

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 capabilities:

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

Bash: how to take a number from string? (regular expression maybe)

Solution

Problem