Shell脚本 - 使用带有/的变量的sed

I am new to shell script and don't know much. I have a set of files on which I want to append some text. I am not sure of a better way to do it, but I am using sed to do so. I have written the following script in bash to do so(I am testing it out with one file out of the set of files in the following). Here, I am replacing I am new to shell script and don't know much. I