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multiple if condition in a bash script

Hi,

I've a question concerning multiple if 'conditions' in bash.

My code looks as follows:

Code:

#!/bin/bash

for i in {1..20..1}

do



  if [[ $i -eq {7 || 11 || 18} ]]

  then

  echo "Welcome $i times"

  fi



done

For example, the 'echo' in the if condition should be for the numbers 7,
11, 18.
But it doesn't do.

Does somebody know how to do that?

Best, grima

Why not use a case statement: 'case $i in 7|11|18) echo "Welcome $i times";; esac;'?

Moved: This thread is more suitable in Programming and has been moved accordingly to help your thread/question get the exposure it deserves.

Hi and welcome to LQ!

Try this:

Code:

#!/bin/bash

for i in {1..20..1}

do



  if [[ $i -eq 7 || $i -eq 11 || $i -eq 18 ]]

  then

  echo "Welcome $i times"

  fi



done

If you only need to match exact number strings, I second colucix's recommendation for a case statement. They're almost always more efficient than if tests.

Code:

#!/bin/bash

for i in {1..20}; do



    case i in

        7|11|18) echo "Welcome $i times" ;;

    esac



done

But if you need to do other numerical comparisons, then a bash "((..))" arithmetic operator is the best choice.

Code:

#!/bin/bash

for i in {1..20}; do

    if (( i == 7 || i == 11 || i >= 18 )); then

        echo "Welcome $i times"

    fi

done

When using bash or ksh, it's recommended to use [[..]] for string/file tests, and ((..)) for numerical tests. Avoid using the old [..] test unless you specifically need POSIX-style portability.

http://mywiki.wooledge.org/BashFAQ/031
http://mywiki.wooledge.org/ArithmeticExpression

And two other minor points:

1) You don't need a step operator in brace expansion if you're just counting by ones anyway.

2) Many scripters also feel that it's better to place the "do/then" keywords on the same line as the "for/while/until/if" keywords, as they are not separate commands but are paired with the opening keyword to bracket the test/input string. Putting them together on one line thus helps to better visually separate the outside block from the inside block.

Scripting With Style