<p>String concatenation does a lot of work without knowing if it is needed or not (the traditional "is debugging enabled" test known from log4j), and should be avoided if possible, as the {} allows delaying the toString() call and string construction to after it has been decided if the event needs capturing or not. By having the logger format a <em>single</em> string the code becomes cleaner in my opinion.</p> shell-script headers (#!/bin/sh vs #!/bin/csh)

This defines what shell (command interpreter) you are using for interpreting/running your script. Each shell is slightly different in the way it interacts with the user and executes scripts (programs).

Since, String is immutable in Java, so the left and right String have to be copied into the new String for every pair of concatenation. So, better go for the placeholder.

When you type in a command at the Unix prompt, you are interacting with the shell.

E.g., #!/bin/csh refers to the C-shell, /bin/tcsh the t-shell, /bin/bash the bash shell, etc.

When you type in a command at the Unix prompt, you are interacting with the shell.

You can tell which interactive shell you are using the

 echo $SHELL

E.g., #!/bin/csh refers to the C-shell, /bin/tcsh the t-shell, /bin/bash the bash shell, etc.

command, or alternatively

 env | grep -i shell

You can tell which interactive shell you are using the

 echo $SHELL

You can change your command shell with the chsh command.

command, or alternatively

 env | grep -i shell

Each has a slightly different command set and way of assigning variables and its own set of programming constructs. For instance the if-else statement with bash looks different that the one in the C-shell.

You can change your command shell with the chsh command.

This page might be of interest as it "translates" between bash and tcsh commands/syntax.

Each has a slightly different command set and way of assigning variables and its own set of programming constructs. For instance the if-else statement with bash looks different that the one in the C-shell.

Using the directive in the shell script allows you to run programs using a different shell. For instance I use the tcsh shell interactively, but often run bash scripts using /bin/bash in the script file.

This page might be of interest as it "translates" between bash and tcsh commands/syntax.

Aside:

Using the directive in the shell script allows you to run programs using a different shell. For instance I use the tcsh shell interactively, but often run bash scripts using /bin/bash in the script file.

This concept extends to other scripts too. For instance if you program in Python you'd put

 #!/usr/bin/python

Aside:

at the top of your Python program

Concatenation is expensive, so you want it to happen only when needed. By using {}, slf4j performs the concatenation only if the trace is needed. In production, you may configure the log level to INFO, thus ignoring all debug traces.

Note: I am the author of this blog post, Logging impact on application performance.

I could not understand BorderThickness="{TemplateBinding BorderThickness}. Here the code:

<ControlTemplate TargetType="{x:Type wpftoolkit:DataGridCell}">
<Border Padding="{TemplateBinding Padding}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Background="{TemplateBinding Background}"
SnapsToDevicePixels="True">
<ContentPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
</ControlTemplate>

Regarding csh, it relates to sh roughly as Nutrimat Advanced Tea Substitute does to tea. It has (or rather had; modern implementations of sh have caught up) a number of advantages over sh for interactive usage, but using it (or its descendant tcsh) for scripting is sh0. If you're new to shell scripting in general, I strongly recommend you ignore it and focus on sh. If you are using a csh relative as your login shell, switch to bash or zsh, so that the interactive command language will be the same as the scripting language you're learning.