Linux Bash Shell Login Primer Tutorial
When you login to Linux the operating system looks to a file called …
/etc/profile
… to perform its commands.
Within that file, if you are in a default Bash environment shell, as we are with Mac OS X application Terminal you may see a line of code, as highlighted in red like …
# System-wide .profile for sh(1)
if [ -x /usr/libexec/path_helper ]; then
eval `/usr/libexec/path_helper -s`
fi
if [ "${BASH-no}" != "no" ]; then
[ -r /etc/bashrc ] && . /etc/bashrc
fi
… which then proceeds to take commands from a file called …
/etc/bashrc
… which may contain code like …
# System-wide .bashrc file for interactive bash(1) shells.
if [ -z "$PS1" ]; then
return
fi
PS1='h:W u$ '
# Make bash check its window size after a process completes
shopt -s checkwinsize
# Tell the terminal about the working directory at each prompt.
if [ "$TERM_PROGRAM" == "Apple_Terminal" ] && [ -z "$INSIDE_EMACS" ]; then
update_terminal_cwd() {
# Identify the directory using a "file:" scheme URL,
# including the host name to disambiguate local vs.
# remote connections. Percent-escape spaces.
local SEARCH=' '
local REPLACE='%20'
local PWD_URL="file://$HOSTNAME${PWD//$SEARCH/$REPLACE}"
printf 'e]7;%sa' "$PWD_URL"
}
PROMPT_COMMAND="update_terminal_cwd; $PROMPT_COMMAND"
fi
Today, we change this /etc/bashrc file so that a current date and time is added to the Linux prompt (and for advice we thank this excellent link) by the amendment in orange as shown below for /etc/bashrc …
# System-wide .bashrc file for interactive bash(1) shells.
if [ -z "$PS1" ]; then
return
fi
PS1='h:W u d [t]$ '
# Make bash check its window size after a process completes
shopt -s checkwinsize
# Tell the terminal about the working directory at each prompt.
if [ "$TERM_PROGRAM" == "Apple_Terminal" ] && [ -z "$INSIDE_EMACS" ]; then
update_terminal_cwd() {
# Identify the directory using a "file:" scheme URL,
# including the host name to disambiguate local vs.
# remote connections. Percent-escape spaces.
local SEARCH=' '
local REPLACE='%20'
local PWD_URL="file://$HOSTNAME${PWD//$SEARCH/$REPLACE}"
printf 'e]7;%sa' "$PWD_URL"
}
PROMPT_COMMAND="update_terminal_cwd; $PROMPT_COMMAND"
fi
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