Tutorial by Examples: t

Simple steps to use scrollview with autolayout. Create a new project with single view application Select the default viewcontroller and change its screen size to iPhone-4inch from attributes inspector. Add a scrollview to your viewcontroller's view as follows and set background color to blue ...

Use "-x" to enable debug output of executed lines. It can be run on an entire session or script, or enabled programmatically within a script. Run a script with debug output enabled: $ bash -x myscript.sh Or $ bash --debug myscript.sh Turn on debugging within a bash script. It may ...

Whitespace matters when assigning variables. foo = 'bar' # incorrect foo= 'bar' # incorrect foo='bar' # correct The first two will result in syntax errors (or worse, executing an incorrect command). The last example will correctly set the variable $foo to the text "bar".

The C standard says that files should end with a new line, so if EOF comes at the end of a line, that line may not be missed by some commands. As an example: $ echo 'one\ntwo\nthree\c' > file.txt $ cat file.txt one two three $ while read line ; do echo "line $line" ; done <...

Every single ViewGroup (e.g. LinearLayout, RelativeLayout, CoordinatorLayout, etc.) needs to store information about its children's properties. About the way its children are being laid out in the ViewGroup. This information is stored in objects of a wrapper class ViewGroup.LayoutParams. To include...

Popular within many open source projects but not only. Master branch of a specific location (Github, Gitlab, Bitbucket, local server) contains the latest shippable version. For each new feature/bug fix/architectural change each developer creates a branch. Changes happen on that branch and can be d...

To execute a script file with the bash interpreter, the first line of a script file must indicate the absolute path to the bash executable to use: #!/bin/bash The bash path in the shebang is resolved and used only if a script is directly launch like this: ./script.sh The script must have exe...

Exit status 0: success Exit status other than 0: failure To test on the exit status of a command: if command;then echo 'success' else echo 'failure' fi

You can do things like this: [[ $s = 'something' ]] && echo 'matched' || echo "didn't match" [[ $s == 'something' ]] && echo 'matched' || echo "didn't match" [[ $s != 'something' ]] && echo "didn't match" || echo "matched" [[ $s -eq...

Will provide the total number of records processed in the current awk instance. cat > file1 suicidesquad harley quinn joker deadshot cat > file2 avengers ironman captainamerica hulk awk '{print NR}' file1 file2 1 2 3 4 5 6 7 8 A total on 8 records were processed in th...

Single file plugin Put the file under $HOME/.vim/plugin or $HOME/vimfiles/plugin This would source the plugin on startup of Vim. Now the user could use everything defined in it. If the plugin however needs activation, the user either has to execute the command themselves whenever they want to use...

See :help packages.

A heredoc uses the limitstring to determine when to stop consuming input. The terminating limitstring must Be at the start of a line. Be the only text on the line Note: If you use <<- the limitstring can be prefixed with tabs \t Correct: cat <<limitstring line 1 line 2 limit...

Press controlr and type a pattern. For example, if you recently executed man 5 crontab, you can find it quickly by starting to type "crontab". The prompt will change like this: (reverse-i-search)`cr': man 5 crontab The `cr' there is the string I typed so far. This is an incremental s...

A classic use of here documents is to create a file by typing its content: cat > fruits.txt << EOF apple orange lemon EOF The here-document is the lines between the << EOF and EOF. This here document becomes the input of the cat command. The cat command simply outputs its in...

You can override 4 methods of SKScene to detect user touch class GameScene: SKScene { override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) { } override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) { ...

If you need to add custom headers to your volley requests, you can't do this after initialisation, as the headers are saved in a private variable. Instead, you need to override the getHeaders() method of Request.class as such: new JsonObjectRequest(REQUEST_METHOD, REQUEST_URL, REQUEST_BODY, RESP_L...

expr or Evaluate expressions evaluates an expression and writes the result on standard output Basic arithmetics expr 2 + 3 5 When multiplying, you need to escape the * sign expr 2 \* 3 6 You can also use variables a=2 expr $a + 3 5 Keep in mind that it only supports integers, so exp...

Most of the built-in operators (including conversion operators) can be overloaded by using the operator keyword along with the public and static modifiers. The operators comes in three forms: unary operators, binary operators and conversion operators. Unary and binary operators requires at least o...

// Shows the author and commit per line of specified file git blame test.c // Shows the author email and commit per line of specified git blame -e test.c file // Limits the selection of lines by specified range git blame -L 1,10 test.c