Checking for the correct number of arguments

Question

How do i check for the correct number of arguments  one argument   If somebody tries to invoke the script without passing in the correct number of arguments  and checking to make sure the command line argument actually exists and is a directory

User · Answer

You can check the total number of arguments which are passed in command line with "$#" Say for Example my shell script name is hello.sh

sh hello.sh hello-world
# I am passing hello-world as argument in command line which will b considered as 1 argument 
if [ $# -eq 1 ] 
then
    echo $1
else
    echo "invalid argument please pass only one argument "
fi

Output will be hello-world

User · Answer

bin sh if        -ne 1          -d   1     then   echo  Usage   0 DIRECTORY   gt  amp 2   exit 1 fi   Translation  If number of arguments is not  numerically  equal to 1 or the first argument is not a directory  output usage to stderr and exit with a failure status code   More friendly error reporting      bin sh if        -ne 1    then   echo  Usage   0 DIRECTORY   gt  amp 2   exit 1 fi if     -e   1     then   echo   1 not found   gt  amp 2   exit 1 fi if     -d   1     then   echo   1 not a directory   gt  amp 2   exit 1 fi

User · Answer

cat script sh      var1  1     var2  2     if        -eq 2       then             if   -d  var1               then             echo directory   var1  exist             else             echo Directory   var1  Does not exists             fi             if   -d  var2               then             echo directory   var2  exist             else             echo Directory   var2  Does not exists             fi     else     echo  Arguments are not equals to 2      exit 1     fi   execute it like below -    script sh directory1 directory2   Output will be like -   directory1 exit directory2 Does not exists

[shell] Checking for the correct number of arguments

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