bash shell scripting

My shell script depends upon user input. How do I find out if a variable called $_JAIL path is empty under Linux / Apple OS X / Unix like operating systems?

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How do I check in GNU/Bash if a shell is running in interactive mode or not while writing shell scripts?

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I‘m using Debian Linux as my development workstation. I would like to search a directory called ~/projects/ recursively for “foo” word only for *.txt files. How do I search all text files in ~/projects/ for “foo” word using grep command?

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How do I determine if a function called foo() is already defined in a bash script or not? If a function called foo() is defined just call it or show an error message?

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Q. How can you test if a file is writable under UNIX / Linux bash shell scripting?

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How do I append additional text a variable? For e.g., I’ve a vech set as follows:
vech=”London”

I’d like to add (append) “Bus” word to $vevh under UNIX scripting using bash?

{ 9 comments }