2015年9月27日 · In bash these are implemented via temp files, usually in the form /tmp/sh-thd.<random string>, while in dash they are implemented as anonymous pipes. This can be observed via tracing system calls with strace command. Replace bash with sh to see how /bin/sh performs this redirection. $ strace -e open,dup2,pipe,write -f bash -c 'cat <<EOF > test ...

2017年1月27日 · help [[returns useful information—since [[an internal bash command—but does not say whether =~ uses basic or extended regex syntax. ⋯ The text you quoted is from the bash man page. I realize you said “read the bash man pages” but at first, I thought you meant read the man pages within bash.

2017年7月25日 · Furthermore, when you use bash -c, behavior is different than if you run an executable shell script, because in the latter case the argument with index 0 is the shell command used to invoke it. As such, I think the way to fix this answer is to change it to execute scripts as files instead of using bash -c, since that's how the asker was doing it.

In general, in bash and other shells, you escape special characters using \. So, when you use echo foo >\> what you are saying is "redirect to a file called >", but that is because you are escaping the second >. It is equivalent to using echo foo > \> which is the same as echo foo > '>'. So, yes, as Sirex said, that is likely a typo in your book.

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

This is not the case with Bash, however, in which both operators have the same precedence, which is why Bash parses your expression using the left-associativity rule. Thanks to Kevin's comment for bringing this up. There might also be cases where all 3 expressions are evaluated.

2020年8月3日 · bash is a command interpreter, a shell, a program with an interface that interprets the commands that you put into it. When you call bash from bash, you simply start a new shell 'inside' the original shell. When you exit from this second shell, you return to the original shell.

2015年3月27日 · The Bash man page's section about read states that, by default... The backslash character (\) may be used to remove any special meaning for the next character read and for line continuation. but, if you pass -r, then. Backslash does not act as an escape character. The backslash is considered to be part of the line.

2010年12月15日 · With . ~/.bashrc, you source your bash. Executing the file would start a child process, execute the commands in this process, then return. All that is done in the child process has no effect on the parent process (the bash from which you executed). Instead, sourcing (with the dot) acts exactly as if you wrote the content of the file in the ...

2011年8月27日 · Shell config files such as ~/.bashrc, ~/.bash_profile, and ~/.bash_login are often suggested for setting environment variables. While this may work on Bash shells for programs started from the shell, variables set in those files are not available by default to programs started from the graphical environment in a desktop session. help.ubuntu.com ...