Dynamic patterns for the Case Statement in Shell Scripting

Question

The code below is just a rough outline of what I am trying to do. Don't worry about what the code is doing after each case is evaluated.

My question is that in the case *','* ) I am trying to recognize a dynamic pattern of files separated by commas.

Ex: getfile.sh -fileextension file1,file2,file3,file4 would be my input. How would i go about recognizing that the input from $2(this is equal to var2) follows the *','* pattern where * represents the file?

    if [ $flag -eq 1 ]; then
            case $var2 in
                #lists files if option is selected
                list | l | LIST | L | ls | LS)      do stuff here
                all | a | ALL | A)                  do stuff here
                *','* )                             do stuff here
                * )                                 do stuff here
            esac
        fi

I should add that the program is supposed to list a set of files based on their extension and then allow the user to either get all those files, or select mutliple (or a single) file. Because i will not know what the user is going to input i'm trying to match a pattern instead of a static input.

So here is what my new code looks like and is much closer to what i'm trying to accomplish:

Let's jsut concentrate on the case so as to not get confused.

case $var2 in
        #lists files if option is selected
        list | l | LIST | L | ls | LS)      ls -1 $DIRECTORY*$extension
                        exit
                        ;;
        #copy all files in the directory
        all | a | ALL | A)  
                        echo ">Cleaning temp dir"
                        allcheck=1
                        cleantemp   
                        copy
                        zip
                        exit
                        ;;
        [0-9][0-9a-zA-Z] | [0-9]','[0-9a-zA-Z]) echo "this is valid input"
                        exit
                        ;;
        * )             
                        echo ">>Bad argument"
                        #help
                        exit 1
                        #fi
    esac

This is the pattern i'm trying to match

[0-9]','[0-9a-zA-Z]

I figured it out after finding a link that gave me a clue: How do I test if a variable is a number in Bash?

Anyways here's what i ended up with:

case $var2 in
        #lists files if option is selected
        list | l | LIST | L | ls | LS)      ls -1 $DIRECTORY*$extension
                        exit
                        ;;
        #copy all files in the directory
        all | a | ALL | A)  
                        echo ">Cleaning temp dir"
                        allcheck=1
                        cleantemp   
                        copy
                        zip
                        exit
                        ;;
        [0-9][0-9a-zA-Z] | [0-9][0-9a-zA-Z],[0-9][0-9a-zA-Z],*) echo "this is valid input"
                        exit
                        ;;
        * )             
                        echo ">>Bad argument"
                        #help
                        exit 1
                        #fi
    esac

This test is for input such as 56 or 5A [0-9][0-9a-zA-Z] This test is for input that is separated by a comma such as what i was tryign to accomplish. [0-9][0-9a-zA-Z],[0-9][0-9a-zA-Z],*

(I will still have to make sure invalid characters are not entered, however, it really cut down on the work i have to do now.)

Thanks for trying to help 'the other guy'.

It's unclear to me what your question is. Are you trying to figure out how to distinguish something with a comma from something without a comma? — Richard Hansen, Jul 04 '13 at 02:37

score 0 · Answer 1 · answered Jul 03 '13 at 17:14

0

Your code correctly matches values of var2 containing commas:

flag=1
var2="file1,file2,file3,file4"
if [ $flag -eq 1 ]; then
    case $var2 in
        #lists files if option is selected
        list | l | LIST | L | ls | LS)      stuff here ;;
        all | a | ALL | A)                  stuff here ;;
        *','* )                             echo "It works" ;;
        * )                                 stuff here ;;
    esac
fi

will print "It works".

If the problem is how to separate a comma separated list, you can use

IFS=","
for file in $var2
do
    echo "Processing $file"
done

answered Jul 03 '13 at 17:14

that other guy

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Sorry, that's not what i'm looking for. I just found something almost to the extent that i'm looking for. Will update soon, maybe you can help me out then. – tc90 Jul 03 '13 at 17:17
Feel free to edit your question to clarify if what you're doing is not actually "recognizing that the input from $2(this is equal to var2) follows the `*','*` pattern". – that other guy Jul 03 '13 at 17:19
I'm not trying to recognize if $2 -eq var2. They are set to equal one another. I'm trying to compare $var2 with potential cases to take appropriate action. sorry for the confusion. – tc90 Jul 03 '13 at 17:22
To see whether "$2" is equal to the contents of the variable "$var2", use `if [[ "$2" = "$var2" ]]; then ...`. To check whether it's equal to the literal string "var2", use `if [[ "$2" = "var2" ]]; then ...` – that other guy Jul 03 '13 at 18:39

Dynamic patterns for the Case Statement in Shell Scripting

1 Answers1