In shell, when you see $ command one && command two the intent is to execute the command that follows the && only if the first command is successful. This is idiomatic of Posix shells, and not only found in Bash. It intends to prevent the running of the second process if the first fails.

In Bash, when you hit enter, a fork + exec + wait happens like above, and bash then sets $? to the exit status of the forked process. Note: for built-in commands like echo, a process need not be spawned, and Bash just sets $? to 0 to simulate an external …

2012年4月3日 · The shell splits tokens based on the contents of the IFS environment variable. Its default value is \t\n ; i.e., whitespace, tab, and newline. Expanding "$@" gives you a pristine copy of the arguments passed.

2024年12月14日 · Bash shell: Bash shell stands for Bourne Again Shell. Bash shell is the default shell in most Linux distributions and substitute for the Sh shell (the Sh shell will also run in the Bash shell). The Bash shell can execute the vast majority of Sh shell scripts without modification and provide commands line editing feature also.

2017年9月3日 · Bash Reference Manual Bash Manual. 3.2.4.3 Grouping Commands. Bash provides two ways to group a list of commands to be executed as a unit. When commands are grouped, redirections may be applied to the entire command list. For example, the output of all the commands in the list may be redirected to a single stream. ( list )

2013年10月18日 · [ ] is actually a shell built-in command, which, can actually be implemented as an external command. Look at your /usr/bin, there is most likely a program called "[" there! Strictly speaking, [ ] is not part of bash syntax. [[ ]] is a shell keyword, which means it is part of shell syntax. Inside this construct, some reserved characters change ...

You can find a very nice reference for bash's [aka test builtin's operators here, or by running help test in a bash shell or info bash test or info bash '[' from any shell¹. If you are using a different shell, just search for the description of its [ or test builtin in its documentation of if it doesn't have such a builtin², in the man page ...

Here shell is an alias for bash and sh. EnlighterJS has nothing for shell sessions. Here shell is an alias for bash. Chroma has something called Session. Pygments uses console, shell-session for bash sessions, pwsh-session, ps1con for power shell sessions and many other non-shell sessions are supported too like interpreter of may languages.

2017年1月27日 · Also beware that shell quoting affects the meaning of RE operators and that some characters need to be quoted for the shell tokenising that may affect the RE processing. [[ '\' =~ [\/] ]] returns false. ksh93 has even worse issues. See zsh (or bash 3.1) for a saner approach

Take a look at the Bash man page. This notation is part of what's called a here documents & here strings. It allows you the ability to generate multi-line data input as one continuous string. The variation you're asking about is called a here string. excerpt from Bash man page