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shell – How to check if a variable is set in Bash?

February 21, 2020 How to Leave a comment

Questions: How do I know if a variable is set in Bash? For example, how do I check if the user gave the first parameter to a function? function a { # if $1 is set ? } How to&Answers: (Usually) The...

How to check if a directory exists in a Bash shell script?

February 21, 2020 How to Leave a comment

Questions: What command can be used to check if a directory exists or not, within a Bash shell script? How to&Answers: To check if a directory exists in a shell script you can use the following: i...

shell – How to concatenate string variables in Bash

February 21, 2020 How to Leave a comment

Questions: In PHP, strings are concatenated together as follows: $foo = "Hello"; $foo .= " World"; Here, $foo becomes “Hello World”. How is this accomplished in Bash? How to&Answers: f...