sed with filename from pipe

Question

In a folder I have many files with several parameters in filenames, e.g (just with one parameter) `file_a1.0.txt`, `file_a1.2.txt` etc. These are generated by a c++ code and I'd need to take the last one (in time) generated. I don't know a priori what will be the value of this parameter when the code is terminated. After that I need to copy the 2nd line of this last file. To copy the 2nd line of the any file, I know that this `sed` command works: ``` sed -n 2p filename ``` I know also how to find the last generated file: ``` ls -rtl file_a*.txt | tail -1 ``` Question: how to combine these two operation? Certainly it is possible to pipe the 2nd operation to that sed operation but I dont know how to include filename from pipe as input to that sed command.

Accepted Answer

You can use this,

```
ls -rt1 file_a*.txt | tail -1 | xargs sed -n '2p'
```

(OR)

```
sed -n '2p' `ls -rt1 file_a*.txt | tail -1`

sed -n '2p' $(ls -rt1 file_a*.txt | tail -1)
```

sed with filename from pipe

Solution

Problem