BioMonth - CSC supercomputing and data management for bioscientists

Prompting — the shell expects something from you

• When executing interactively, bash displays the primary prompt string PS1 when it is ready to read a command, and the secondary prompt PS2 when it needs more input to complete a command.
• Bash allows these prompt strings (environment variables) to be customized. A number of backslash-escaped special characters can be used to display various information.

$ PS1="(\!) \h:\W\$ "

\\!	history number of this command
\\h	hostname up to the first .
\\W	the basename of current working directory
\\$	if effective UID is 0, a #, otherwise a $

Look at the prompt string in your machine. Can you figure out how it is built?

Can you figure out what this shell functin does (hint, run it…in a subshell)?

tutorial_prompt () {
    FONT_RESET=$(tput sgr0)
    FONT_BOLD=$(tput bold)
    PS1="\[${FONT_RESET}\]\w \$ \[${FONT_BOLD}\]"
    trap 'echo -ne "${FONT_RESET}" > $(tty)' DEBUG
}

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