In this article, we will see how to check if output contains String in Bash using grep, Conditional Expressions, awk, sed commands with various options.
we are using the Bash instruction to run this Bash file, i.e., empty.sh. On execution, it returns “Empty” because the string “str” is initialized empty in the code, and the “then” part of the “if-else” statement has been executed so far. ...
/bin/bash #Take the filename echo-n"Enter the filename: " readfilename #Check whether the file exists or not using the -f operator if[-f"$filename"];then echo"File exists." else echo"File does not exist." fi The script is executed twice in the following script. The non-existence...
Afterdeclaring a string variable, use the-zoperator in anif statementto check whether a string is empty or not: MY_STRING="" if [ -z $MYSTRING ] then echo "String is empty" else echo "String is not empty" fi For more Shell scripting tips,check out or Bash/Shell scripting articles!
How to Check if String Contains a Substring in Bash So, you have a long string and you want to check of this string contains a substring in your bash script. There are more than one way to check for substrings in bash shell. I'll show some simple examples first, followed by a cool...
In Bash, you can use the test command to check whether a file exists and determine the type of the file.The test command takes one of the following syntax forms: test EXPRESSION [ EXPRESSION ] [[ EXPRESSION ]] Copy If you want your script to be portable, you should prefer using the ...
#!/bin/bash file1="/home/user/File1.txt" file2="/home/user/File2.txt" if cmp -s "$file1" "$file2"; then echo "Both files are the same." else echo "Both files are different." fi OUTPUT 1 2 3 Both files are the same. In the above example, we initialized the file1 ...
The easiest way to check if a file exists is to use thetestcommand. With-f <file-name>option, thetestcommand returns true if the specified file exists. FILE=/etc/pam.conf if test -f $FILE; then echo "$FILE exists" fi Alternatively, you can use thebash's built-in flag-f, which ...
Check empty bash array with string comparison We are going to use two elements to check if bash array is empty or not. One is${#array[@]}and other is the-zoperator. Here, the${#array[@]}is used in Bash for array expansion, allowing you to access all elements of an array.Don't...
One of the most common operations when working with strings in Bash is to determine whether or not a string contains another string. In this article, we will show you several ways to check if a string contains a substring.