Shell Programming and Scripting

Hi everyone,

I must make a script which will be executed as follows :

./script.sh Directory/n[0-9].car where there can be as many numbers as we may want.

I'd like to : - ignore the Directory ; Meaning I just need n[0-9].car
- Check the name of the file : has it got some Alphabetic Characters after the n? in which case it's not a proper file name.
- *Extract* the number in the name, to be able to compare it to something else after.

Thanks in advance,

~ Lyth_o ~

At least an idea to work with:

Code:

FILE=$( basename $1 )
CORE=$( echo $FILE | sed '/s/^n//' | sed 's/$\.car//' )
TEST=$( echo $CORE | egrep -o '[[:alpha:]]' )
if [ -n "$TEST" ]
then
  echo "File name not valid!"
fi

Ok thank you.
I'll try to understand sed's use. (I have never understood what it does or how to use it...)
^^

Presuming you do not literally mean ./script.sh Directory/n[0-9].car which is a globbing expression which may expand to multiple files as input, but that you mean a single file that consists of an n followed by multiple digits (n>=1) followed by the extension .car:

If so, you could try this alternative which uses no external programs:

Code:

no_n="${1##*/n}"
nr="${no_n%.car}"
case $nr in
  *[^0-9]*) echo "File name ${1##*/} invalid.."
esac

Here is another way - remove digits from the basename of the file spec and you get "n.car" for good files.

Code:

if [[  $(basename $filename | tr -d '[:digit:]') = "n.car" ]] ; then
   echo "$filename is ok"
else
   echo "$filename is not ok"
fi

Bash/ksh:

Code:

if [[ ! ${1//[0-9]} =~ .*/?n.car ]]; then
  echo "File name ${1##*/} invalid.."
fi

Thank you everyone.

I took Scrutinizer's first option.

Does your second option do the same?

Do you know how to get the last character of a line?

I have the code :

echo `$1 $2`

And I would like to compare the last character of the result (which is a number) with a certain number...

Edit : I have found something working...

But, does someone know how to echo something when executing `$1 $2` ($1 is ./program and $2 an argument of it) provokes an error?