Shell Programming and Scripting

Hi guys i have this task for exam in 2 days and i cant solve it.
So i need when i give my script a path to a file,it needs to recognize what tool to use to unpack it.
for exmp
file.tar.gz tar zxf file.tar.gz
file.tar tar xf file.tar
file.zip unzip file.zip
file.tar.bz2 tar jxf file.tar.bz2
file.bz2 gunzip2 -d file.bz2
So i need someone to tell me how do i write the line so script can read how the file ends?
im rly bad with "if" but if u can just write 1 code line like this itryed :
#!/bin/bash
if [ "$1" == "*.tar" ] ; then
tar xf *.tar
fi

you need to isolate the extension first (see hint below) ... see "man awk" for questions on what i am using ... be aware that you would also need to differentiate between .tar.* and .tar so you may also need to isolate the preceding extensions (i.e., tar) if any ... read up on the threads within the shell programming forum for more hints ... good luck on your exam!

Code:

echo file.tar.gz | awk -F"." '{print $NF}' | grep ".gz"
if [ $? -eq 0 ]
then
      echo "file.tar.gz is a gzip file"
fi

In if you cannot simply test on wild cards. This is a case for case!

Code:

case "$1" in
*.tar)
  tar xf "$1"
  ;;
*.tar.gz)
  ...
  ;;
esac

using case is definitely much more efficient here ...

the object of the exercise, however, was to give the student a hint on how to deal with the problem himself without doing the work for him. he will learn of the many other ways he can get things done as he goes along.

Thanx a lot guys!