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Quick Linux Tip 🐧 In Linux, the pipe(|) operator is very useful if you want to redirect the output of one command to serve as input to the next for further processing: $ cat data.conf | grep "No such file" However, this does not redirect the errors. So, if the file does not exist, the grep command above will not return a match. What if you want to redirect and process both errors and normal output🤔 This is where this "|&" redirection operator comes in handy. This operator sends both the standard output (stdout) and standard error (stderr) of the first command over a pipe to the standard input (stdin) of the second command. Take a look at this example: $ cat data.conf |& grep "No such file" Notice the difference, the grep command was able to get a match. The "|&" operator in bash is a shorthand for the "2>&1 |" redirection operator. $ cmd-1 2>&1 | cmd-2

📚 A Quick Guide to Bash Special Variables: • $1, $2, $3, ... These are the positional parameters, representing arguments passed to the script or function. $1 is the first argument, $2 is the second, and so on. • "$@" An array-like construct containing all positional parameters. Each parameter is treated as a separate quoted string, preserving spaces. • "$*" Expands all positional parameters as a single string, separated by the current Internal Field Separator (IFS). • $# The number of positional parameters passed to the script or function. • $- Displays the current shell options as a string (e.g., himBH for interactive, monitor mode, etc.). • $$ The process ID (PID) of the current shell instance, not any subshell it may invoke. • $_ Holds the last argument of the previous command or the absolute path of the shell script executed at startup. • $IFS The Internal Field Separator, used to split input into fields during expansion. Defaults to spaces, tabs, and newlines. • $? The exit status of the last executed command. A value of 0 typically means success, while non-zero indicates an error. • $! The PID of the most recently executed background command. • $0 The name of the script or shell being executed, including its path if run with one.

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