Bash如何检查参数是否为sed模式？

Question

I'm working on a bash script that should receive many arguments. those arguments could be simple like:

Myscript [-r] [-l|-u] <dir/file names...>

or it could be just a sed patterns given instead of a simple arguments like:

Myscript  <sed pattern> <dir/file names...>

So my question is how to check if the arguments given is a sed patterns and not directory path or filename? I have done something but it doesn't work for a long path ( dir1/dir2/dir )

    while [[ $# > 0 ]]
    do
    key="$1"

    case $key in

        -ru|-ur)
            config_recusive
            config_upper
            shift
            ;;
        -rl|-lr)
            config_recusive
            config_lower
            shift
            ;;
        -r)
            config_recusive
            shift
            ;;
        -l)
            config_lower
            shift
            ;;
        -u)
            config_upper
            shift
            ;;
        *)
            check="^.*/.*/.*$"
            if [[ $key =~ $check ]] ; then 

                config_sed_pattern
            else
                TARGET=$key      
            fi
            shift
            ;;
    esac
done

To be more clear, here is an example of my problem when I'm trying to run the script like that:

./myscript -u tmp/users/regions

its being confused taking the path ( tmp/users/regions ) as a sed patterns. hope that I was clear enough. waiting for your help :) thanks

Answer 1

i think you could use try run that script on something

echo a | sed "$pattern" >/dev/null 2>/dev/null

and then check the $?

if [ $? != 0 ]; then # means sed failed
#...

but maybe sed will think it will be its argument too.

btw, handle arguments using getopt will make things easier.

i don't think the way you design argument format is good. maybe you think making arguments in different forms could make your program looks dynamic and awesome. but now you are trying to solve a problem have nothing to do with your serious business and wasting your own time and ours. that's not good. it's better to make things stupid and clear.

in your case, maybe you can add another argument to show it's a sed expression that follows.

YourScript -e <sed expr> <others>

and in such a way, you will have idea about what you have done two weeks later.