CODEWITHSUNDEEP
shellif-statementecho
Parth Mangukiya
Parth Mangukiya

Reputation: 454

Why echo function is not printing anything here?

In this shellscript, I have created 3 functions. It will take 2 command line arguments. first for the type of the operation and second for a string to perform something on it.. Here, my echo command in any of the functions is not printing anything..

Any Help would be appreciated.

clear

lower()
{
echo $2 | tr "[A-Z]" "[a-z]"
}

upper()
{
echo $2 | tr "[a-z]" "[A-Z]"
}

proper()
{
echo $2 | sed 's/.*/\L&/; s/[a-z]*/\u&/g'
}


#echo "Enter The Option and then the string to perform the operation:"
echo $1 $2 '> echo $1 $2 '

if [ $1 = "-l" ]
then
lower $2
elif [ $1 = "-u" ]
then
upper $2
elif [ $1 = "-p" ] 
then 
proper $2
fi

Upvotes: 3

Views: 5498

Answers (2)

John Kugelman
John Kugelman

Reputation: 361605

Outside of a function, $1, $2, etc., refer to the command-line arguments to the program. Inside of a function, they are the function's arguments. Change all of the echo $2's to echo $1.

Style improvements:

  • By default, always quote variable expansions. Write "$1" and "$2" instead of bare $1 and $2. That way if those arguments have spaces or globs they'll expand to one word instead of many.

  • The if/elif chain at the bottom could be replaced with a case block.

    case "$1" in
    -l) lower "$2";;
    -u) upper "$2";;
    -p) proper "$2";;
esac

  • Putting clear at the top of a script is kind of an annoying DOS-ism. On Linux, I don't want scripts I run clearing my terminal as if they know best. Either get rid of the clear; or, if you want to be fancy, add tput smcup at the top and tput rmcup at the bottom to save and restore the terminal. That's what programs like less and vim do to draw to the whole screen and then restore the original terminal contents when they exit.

Upvotes: 2

iamauser
iamauser

Reputation: 11479

Inside each function, replace $2 with $1.

  lower()
  {
    echo $1 | tr "[A-Z]" "[a-z]"  
  }

For your script and also for your function, $1 represents the first argument and $2 second. If you are going to provide two arguments to your script, but one argument to your function, then it should be,

$ cat test.sh
#!/bin/bash

echo "$1" "$2"

func_echo(){
 echo "func $1"
}
# Call the function
func_echo $2

Resulted in:

$ ./test.sh "first" "second"
first second
func second

Upvotes: 1

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