What does F mean in bash?
It’s the first hit when you Google for “Bash manual”.
§6.4 “Bash Conditional Expressions” says: -f file.
True if file exists and is a regular file..
What does $? Mean in shell script?
$? Stores the exit value of the last command that was executed. $0 Stores the first word of the entered command (the name of the shell program). $* Stores all the arguments that were entered on the command line ($1 $2 …).
What does $$ mean in bash?
The $$ is the process id of the shell in which your script is running. For more details, see the man page for sh or bash. The man pages can be found be either using a command line “man sh”, or by searching the web for “shell manpage”
What is $$ in bash?
bash script parameter is used to reference the process ID of the most recently executed command in background. $$ $$ is used to reference the process ID of bash shell itself. $# $# is quite a special bash parameter and it expands to a number of positional parameters in decimal.
What are shell scripts used for?
Shell scripts are commonly used for many system administration tasks, such as performing disk backups, evaluating system logs, and so on. They are also commonly used as installation scripts for complex programs.
What is Echo $$ in Linux?
echo is one of the most commonly and widely used built-in command for Linux bash and C shells, that typically used in scripting language and batch files to display a line of text/string on standard output or a file.
What does $0 mean in shell script?
Purpose. $0 expands to the name of the shell or shell script. This is set at shell initialization. If bash is invoked with a file of commands, $0 is set to the name of that file.
What is $3 in shell script?
$0 is the name of the script itself, $1 is the first argument, $2 the second, $3 the third, and so forth.
What does $$ mean in Linux?
$$ means the process ID of the currently-running process.
What is Echo $1?
$1 is the argument passed for shell script. … But if you’ll write and run your own script in current session, $1, $2, … will be parameters that you send to your script.