Loop through an array of strings in Bash?

## declare an array variable
declare -a arr=("element1" "element2" "element3")

## now loop through the above array
for i in "${arr[@]}"
do
   echo "$i"
   # or do whatever with individual element of the array
done

# You can access them using echo "${arr[0]}", "${arr[1]}" also

from : https://stackoverflow.com/questions/8880603/loop-through-an-array-of-strings-in-bash

In Bash, how can I check if a string begins with some value?

This snippet on the Advanced Bash Scripting Guide says:

# The == comparison operator behaves differently within a double-brackets
# test than within single brackets.

[[ $a == z* ]]   # True if $a starts with a "z" (wildcard matching).
[[ $a == "z*" ]] # True if $a is equal to z* (literal matching).

string='My long string'
if [[ $string == *"My long"* ]]; then
  echo "It's there!"
fi

from : https://stackoverflow.com/questions/2172352/in-bash-how-can-i-check-if-a-string-begins-with-some-value

Print array elements on separate lines in Bash?

Try doing this :

$ printf '%s\n' "${my_array[@]}"

from : https://stackoverflow.com/questions/15691942/print-array-elements-on-separate-lines-in-bash

Create array in loop from number of arguments

You can use the += operator to append to an array.

args=()
for i in "$@"; do
    args+=("$i")
done
echo "${args[@]}"

from : https://stackoverflow.com/questions/15420790/create-array-in-loop-from-number-of-arguments

Run bash command on jenkins pipeline

The Groovy script you provided is formatting the first line as a blank line in the resultant script. The shebang, telling the script to run with /bin/bash instead of /bin/sh, needs to be on the first line of the file or it will be ignored.

So instead, you should format your Groovy like this:

stage('Setting the variables values') {
    steps {
         bash '''#!/bin/bash
                 echo "hello world" 
         '''
    }
}

from : https://stackoverflow.com/questions/44330148/run-bash-command-on-jenkins-pipeline

Is there a better way to write this null check, and a non-empty check, in groovy?

There is indeed a Groovier Way.

if(members){
    //Some work
}

from : https://stackoverflow.com/questions/17256855/is-there-a-better-way-to-write-this-null-check-and-a-non-empty-check-in-groovy/17256864

Check if a file exists in jenkins pipeline

def exists = fileExists 'file'

if (exists) {
    echo 'Yes'
} else {
    echo 'No'
}

from : https://stackoverflow.com/questions/38534781/check-if-a-file-exists-in-jenkins-pipeline