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 copy of the arguments passed. Expanding $@ may not.

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 the shell option nocasematch is enabled, the match is performed without regard to the case of alphabetic characters.

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 (default "success" return value). If it doesn't exist, you should get a number other then 0. The exact number depends on the program.

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 how many parameters are given with code like this: if [ "$#" -eq 0 ]; then echo "you did not pass any parameter" fi

What is the difference between =, == and -eq in shell scripting? Is there any difference between the following?

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 now prints the message twice. The colon method gets round that.

I can't seem to be able to increase the variable value by 1. I have looked at tutorialspoint's Unix / Linux Shell Programming tutorial but it only shows how to add together two variables. I have tried the following methods but they don't work:

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 by the shell. For a comprehensive index, please see the Reference Manual Variable Index.

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, C shell, Z shell, etc. Using any of the shell programs, we will be able to execute commands that are supported by that shell program. Bash - It derived from Bourne ...

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 should always quote shell variables unless you have a good reason not to, and you’re sure you know what you’re doing. By contrast, while braces can be ...