What is the meaning of a bash variable used like this: ${Server?} Answer It works almost the same as (from the bash manpage): ${parameter:?word} Display Error if Null or Unset. If parameter is null or unset, the expansion of word (or a message to that effect if word is not present) is written to the … Read more
I am running Eclipse Helios and I have g++-4.6 installed. Hope I am not wrong that g++4.6 implements C++ 11 features. I have created a C++ project which uses the nullptr and auto keywords. The build gives the following errors:- ../{filename}.cpp:13:13: error: ‘nullptr’ was not declared in this scope ../{filename}.cpp:14:2: warning: ‘auto’ will change meaning … Read more
I need to search a pattern in a directory and save the names of the files which contain it in an array. Searching for pattern: grep -HR “pattern” . | cut -d: -f1 This prints me all filenames that contain “pattern”. If I try: targets=$(grep -HR “pattern” . | cut -d: -f1) length=${#targets[@]} for ((i … Read more
I’ve used regexp package to replace bellow text {% macro products_list(products) %} {% for product in products %} productsList {% endfor %} {% endmacro %} but I could not replace “products” without replace another words like “products_list” and Golang has no a func like re.ReplaceAllStringSubmatch to do replace with submatch (there’s just FindAllStringSubmatch). I’ve used … Read more
What will this command do? exec 2>&1 Answer Technically speaking it duplicates, or copies, stderr onto stdout. Usually you don’t need the exec to perform this. A more typical use of exec with file descriptors is to indicate that you want to assign a file to an unused file descriptor, e.g. exec 35< my_input BTW … Read more
I fail to understand how to correctly assure that something is not nil in this case: package main type shower interface { getWater() []shower } type display struct { SubDisplay *display } func (d display) getWater() []shower { return []shower{display{}, d.SubDisplay} } func main() { // SubDisplay will be initialized with null s := display{} … Read more
How to pass variable length arguments in Go? for example, I want to call func MyPrint(format string, args …interface{}) { fmt.Printf(“[MY PREFIX] ” + format, ???) } // to be called as: MyPrint(“yay %d”, 213) // or MyPrint(“yay”) // or MyPrint(“yay %d %d”,123,234) Answer Ah found it…functions that accept variable length arguments are called Variadic … Read more
This question already has answers here: How can I pipe stderr, and not stdout? (11 answers) Closed 5 years ago. I want to lint a file, and print the stderr (error message), but do not print the stdout (saying the file is OK). php -l “foo/bar.php” If there are no errors, it prints a “No … Read more
I have a repository that uses Travis CI, and in the .travis.yml there I have this line: script: – vim -Nu <(cat <<-EOF set nocompatible | filetype off EOF ) -c ‘Script’ > /dev/null Sadly this doesn’t work, as this is transformed into a single line and is executed like this: vim -Nu <(cat <<-EOF … Read more
I’ve seen people say just create a new slice by appending the old one *slc = append(*slc[:item], *slc[item+1:]…) but what if you want to remove the last element in the slice? If you try to replace i (the last element) with i+1, it returns an out of bounds error since there is no i+1. Answer … Read more
