使用Getopts传递多个强制性标志的问题

Question

I'm currently working on a script and I'm having a tough time wrapping my head around using multiple flags with mandatory arguments. For the sake of brevity, I have scaled it down to two options (even though its still pretty long)

#THE NAME OF THE SCRIPT IS testfind.sh
#!/bin/bash

while getopts :f:d: opt
do
case $opt in
f)                                #With the flag (-f), we run a find command to search
    fOption=$OPTARG               #for all files. The $OPTARG is the directory the user
    find ${fOption} -type f       #gives the command to start the search. Same concept
    ;;                            #with flag (-d) except it runs find on directories.
d)                   
    dOption=$OPTARG
    find ${dOption} -type d
    ;;
esac
done
shift $((OPTIND -1))

If I were to run the command with only one of the two flags, it runs fine. I am piping to wc -l for testing. For clarity, I will use the number of files and directories my system shows:

./testfind.sh -f /home | wc -l            #WORKS FINE, puts out a count of 342
./testfind.sh -d /home | wc -l            #WORKS FINE, puts out a count of 1996
./testfind.sh -d /home -f /home | wc -l   #WORKS FINE, puts out count of 2338, (total of d and f)

Now here's for the flag of 1 and 2

./testfind.sh -df /home | wc -l           #FAILS, RUNS FIRST FLAG BUT NOT 
                                          #THE SECOND. It will only run whichever
                                          #flag I put in first.

I'm trying to make the last line above ^ work so that it put out the output of d and f at the same time (-df). Is there any way to do this in GetOpts?

Answer 1

Getopts supports taking multiple statements, however it will not take multiple statements with mandatory statements. As we saw above, the following did not work:

./testfind.sh -df /home | wc -l

When we look at all of the flag options we fed getopts, we see the following

getopts :f:d: opt

Note: This is where I made the mistake. Both the f and the d flag are expecting a mandatory statement at the end. Since getopts does not support this, instead of reading f as a second flag, it is reading it as if it were the mandatory statement itself. To bypass this, I did the following:

#!/bin/bash

while getopts :fd opt  #NOTE: ONLY USE SHORT FLAGS! THIS WAY, GET OPTS
do                     #CAN EASILY CALL ON WHATEVER YOU THROW AT IT.
                       #MULTIPLE MANDATORY ARGUMENTS NOT SUPPORTED BY GETOPTS.
case $opt in
f)                        
    fOption=$OPTARG    #The variable ${2} is where all the power in this
    find ${2} -type f  #Script lies. By default, getOpts is taking every
    ;;                 #Argument you throw at it after the name of the
                       #Script. In this case It's everything after
d)                     #./testfind.sh . For Example, it took -df and set
    dOption=$OPTARG    #-df to $1. The same way, it takes /home and set
    find ${2} -type d  #/home itself to $2. 
    ;;
esac
done
shift $((OPTIND -1))

Everything needed is explained in the comments (to the right of the #). This same concept will now work with any directory and flags you throw at it. As long as the flags are valid and the directory is valid, it will find whatever you need and print it out in any order you want. You can even throw ./testfind -dfdfdfdfdfdfdfdf /home and it will print every single flag in the directory you fed it. Neato aye!

-Credits to Mark Plotnick for his comment highlighting how getopts was reading the flags with mandatory statements. Thanks!