Question: If I have 10 files called 01-a.txt, 02-a.txt,...10-a.txt - how can I find the files where the number is greater than 5? I would like a general solution, and I would be putting the contents of all files into one file using something like

```
cat *.txt > bigfile.txt

```

I can get files with numbers using

```
ls *[0-9]*

```

but can't seem go beyond that.

thanks.

Answer: 
You may use `seq` for that, but it works only if all files have same naming convention:

```
seq -f "%02g-a.txt" 6 10
06-a.txt
07-a.txt
08-a.txt
09-a.txt
10-a.txt

```

I.e.: 

```
cat `seq -f "%02g-a.txt" 6 10` > bigfile.txt

```
```
ls *.txt | perl -n -e '$f = $_; $f =~ s/\D//g; $f > 5 and print'

```