在 case 语句中使用 grep 命令

Question

So I have this script which im trying to determine the type of the file and act accordingly, I am determining the type of the file using file command and then grep for specific string, for example if the file is zipped then unzip it, if its gzipped then gunzip it, I want to add a lot of different types of file.

I am trying to replace the if statements with case and can't figure it out

My script looks like this:

##$arg is the file itself 

TYPE="$(file $arg)"

if [[ $(echo $TYPE|grep "bzip2") ]] ; then

 bunzip2 $arg

elif [[ $(echo $TYPE|grep "Zip") ]] ; then

  unzip $arg

fi

Thanks to everyone that help:)

Answer 1

The general syntax is

case expr in
  pattern) action;;
  other) otheraction;;
  *) default action --optional;;
esac

So for your snippet,

case $(file "$arg") in
  *bzip2*) bunzip2 "$arg";;
  *Zip*)   unzip "$arg";;
esac

If you want to capture the file output into a variable first, do that, of course; but avoid upper case for your private variables.

bzip2 and unzip by default modify their input files, though. Perhaps you want to avoid that?

case $(file "$arg") in
  *bzip2*) bzip2 -dc <"$arg";;
  *Zip*)   unzip -p "$arg";;
esac |
grep "stuff"

Notice also how the shell conveniently lets you pipe out of (and into) conditionals.