I am using `sed` in `bash shell script`. I want to add some text, which is defined as shell variable, in the first place of each line using `sed`.

For example,

```
cat filename
1.cfg
2.cfg
...
100.cfg

```

In the script,

```
#!/bin/bash
currentd="/home/test/"
sed "/WHAT SHOUL I DO to add $currentd/" filename > filepath

```

I want to add the file path `currentd` in the first place of the each line in `filename` and get `filepath` file.