(From the Bash man page: "Any part of the pattern may be quoted to force it to be matched as a string."). Here in Bash, the two statements yielding "yes" are pattern matching, other three are string equality:

2019年8月1日 · From the manual: (acessible by calling man bash in your shell) Expands to the exit status of the most recently executed foreground pipeline. By convention an exit status of 0 means success, and non-zero return status means failure.

2021年10月27日 · Good in REPL, but for scripts I would prefer set -o errexit for Bash. – Franklin Yu. Commented Feb 11, ...

2017年1月18日 · Bash scripting missing ']' [closed] Ask Question Asked 11 years, 10 months ago. Modified 4 years, 6 ...

2012年4月3日 · * Note: Word splitting. 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.

2012年9月14日 · Most of the above can be found under Special Parameters in the Bash Reference Manual. Here are all the environment variables set by the shell. For a comprehensive index, please see the Reference Manual Variable Index .

[[is a bash is bash-specific, though others shells may have implemented similar constructs. Don't expect it in an old-school UNIX sh. == and != apply bash pattern matching rules, see "Pattern Matching" in man bash; has a =~ regex match operator; allows use of parentheses and the !, &&, and || logical operators within the brackets to combine ...

2013年7月17日 · If you use man bash instead of info bash, search for ^ *test (the word test at the beginning of a line, following some number of spaces). Following the reference to "Bash Conditional Expressions" will lead you to the description of -ne , which is the numeric inequality operator ("ne" stands for "not equal).

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 …

2015年3月25日 · I often come across $? $0 $1 $2 etc.... in shell scripting, what I know is that $? returns the exit status of the last command echo "this will return 0" echo $? but what do the others do? what ar...