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regex - Meaning of "=~" operator in shell script - Stack Overflow
Sep 17, 2012 · The return value is 0 if the string matches the pattern, and 1 otherwise. If the regular expression is syntactically incorrect, the conditional expression's return value is 2. If …
linux - What does $@ mean in a shell script? - Stack Overflow
Apr 3, 2012 · The shell splits tokens based on the contents of the IFS environment variable. Its default value is \t\n; i.e., whitespace, tab, and newline. Expanding "$@" gives you a pristine …
What is the $? (dollar question mark) variable in shell scripting?
Try the following in the shell: ls somefile echo $? If somefile exists (regardless whether it is a file or directory), you will get the return value thrown by the ls command, which should be 0 …
What does $# mean in shell? - Unix & Linux Stack Exchange
You can always check the man page of your shell. man bash says: Special Parameters # Expands to the number of positional parameters in decimal. Therefore a shell script can check …
What is the purpose of the : (colon) GNU Bash builtin?
Jul 12, 2010 · The first line, set -x, makes the shell print out the command before running it. It's quite a useful construct. The downside is that the usual echo Log message type of statement …
What is the meaning of $? in a shell script? - linux
Feb 20, 2011 · This latter usage is faster, does not contaminate the shell's variable namespace with what amounts to temp variables, can often be a lot more readable for humans and …
What are the special dollar sign shell variables? - Stack Overflow
Sep 14, 2012 · $0 is the name of the shell or shell script. Most of the above can be found under Special Parameters in the Bash Reference Manual. Here are all the environment variables set …
Difference between $ {} and $ () in a shell script - Super User
The above (along with many more forms of ${parameter…something_else} constructs) are discussed at greater length in the shell’s man page, bash(1). A Note on Quotes. Note that you …
Meaning of $? (dollar question mark) in shell scripts
The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed. [...]? Expands to the exit status of the most recently …
shell - Difference between sh and Bash - Stack Overflow
Dec 14, 2024 · Shell - "Shell" is a program, which facilitates the interaction between the user and the operating system (kernel). There are many shell implementations available, like sh, Bash, …