How do you check which bash we are using?
To test the above, say bash is the default shell, try echo $SHELL , and then in the same terminal, get into some other shell (KornShell (ksh) for example) and try $SHELL . You will see the result as bash in both cases. To get the name of the current shell, Use cat /proc/$$/cmdline .
Can shell script accept arguments?
Arguments can be passed to the script when it is executed, by writing them as a space-delimited list following the script file name. Inside the script, the $1 variable references the first argument in the command line, $2 the second argument and so forth. The variable $0 references to the current script.
How do I know if Im using Bash or zsh?
Update your Terminal preferences to open the shell with the command /bin/bash , as shown in the screenshot above. Quit and restart Terminal. You should see “hello from bash”, but if you run echo $SHELL , you will see /bin/zsh .
What happens when Bash is invoked in a script?
When Bash is invoked in this fashion, $0 is set to the name of the file, and the positional parameters are set to the remaining arguments. Bash reads and executes commands from this file, then exits. Bash’s exit status is the exit status of the last command executed in the script.
What to do when Bash is not interactive?
When the shell is interactive, this is equivalent to starting a login shell with ‘ exec -l bash ’. When the shell is not interactive, the login shell startup files will be executed. ‘ exec bash -l ’ or ‘ exec bash –login ’ will replace the current shell with a Bash login shell.
Which is the invocation option in Bash for login?
If the invocation option is +O, the output is displayed in a format that may be reused as input. A — signals the end of options and disables further option processing. Any arguments after the — are treated as filenames and arguments. A login shell is one whose first character of argument zero is ‘ – ’, or one invoked with the –login option.
How does Bash read commands from a file?
When Bash is invoked in this fashion, $0 is set to the name of the file, and the positional parameters are set to the remaining arguments. Bash reads and executes commands from this file, then exits.