In this tutorial, learn different ways to append string variables
There are multiple ways to check if a string contains a substring
Simple variable append
Declare two string variables in the bash script printed to console using echo by appending(enclosed in a double quote with variable syntax)
string1="Hello, "
string2='Welcome to w3schools.'
echo "$string1 $string2 "
You can also append without a double quote
echo $string1 $string2
Output:
Hello, Welcome to w3schools.
Another example is to concatenate a string to the same variable and print it to console
result="My site is"
result="${result} w3schools"
echo "${result}"
Output:
My site is w3schools
Append strings using shorthand arithmetic operator
shorthand arithmetic operator(+=) is used in numbers to add value to the variable and save the result to the variable.
This can also be used for strings to append a string to a variable.
For example,
a+=1 is equal to a=a+1 in case of numbers
str+=“test” will become str=str+“test” in the case of strings
Here is an example code
nums="One Two"
nums+=" three"
echo "$nums"
Output:
One Two three
Substring checks using the grep command
The grep command searches for a given string and piped to the main string to compare it
mainstring='Welcome to w3schools'
if echo "$mainstring" | grep -q "w3schools"; then
echo "w3schools exists in the main string"
fi
