{"id":9645,"date":"2014-09-16T05:05:16","date_gmt":"2014-09-15T19:05:16","guid":{"rendered":"http:\/\/www.rjmprogramming.com.au\/wordpress\/?p=9645"},"modified":"2015-05-23T14:27:05","modified_gmt":"2015-05-23T04:27:05","slug":"linux-bash-shell-login-primer-tutorial","status":"publish","type":"post","link":"https:\/\/www.rjmprogramming.com.au\/ITblog\/linux-bash-shell-login-primer-tutorial\/","title":{"rendered":"Linux Bash Shell Login Primer Tutorial"},"content":{"rendered":"
\"Linux<\/a>

Linux Bash Shell Login Primer Tutorial<\/p><\/div>\n

When you login to Linux the operating system looks to a file called …<\/p>\n

\/etc\/profile<\/p>\n

… to perform its commands.<\/p>\n

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<\/font> like …<\/p>\n


\n# System-wide .profile for sh(1)<\/p>\n

if [ -x \/usr\/libexec\/path_helper ]; then
\n\teval `\/usr\/libexec\/path_helper -s`
\nfi<\/p>\n

if [ \"${BASH-no}\" != \"no\" ]; then
\n\t[ -r \/etc\/bashrc ] && . \/etc\/bashrc<\/font>
\nfi
\n<\/code><\/p>\n

… which then proceeds to take commands from a file called …<\/p>\n

\/etc\/bashrc<\/p>\n

… which may contain code like …<\/p>\n


\n# System-wide .bashrc file for interactive bash(1) shells.
\nif [ -z \"$PS1\" ]; then
\n return
\nfi<\/p>\n

PS1='h:W u$ '
\n# Make bash check its window size after a process completes
\nshopt -s checkwinsize
\n# Tell the terminal about the working directory at each prompt.
\nif [ \"$TERM_PROGRAM\" == \"Apple_Terminal\" ] && [ -z \"$INSIDE_EMACS\" ]; then
\n update_terminal_cwd() {
\n # Identify the directory using a \"file:\" scheme URL,
\n # including the host name to disambiguate local vs.
\n # remote connections. Percent-escape spaces.
\n\tlocal SEARCH=' '
\n\tlocal REPLACE='%20'
\n\tlocal PWD_URL=\"file:\/\/$HOSTNAME${PWD\/\/$SEARCH\/$REPLACE}\"
\n\tprintf 'e]7;%sa' \"$PWD_URL\"
\n }
\n PROMPT_COMMAND=\"update_terminal_cwd; $PROMPT_COMMAND\"
\nfi<\/p>\n

<\/code><\/p>\n

Today<\/a>, 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<\/a>) by the amendment in orange<\/font> as shown below for \/etc\/bashrc …<\/p>\n


\n# System-wide .bashrc file for interactive bash(1) shells.
\nif [ -z \"$PS1\" ]; then
\n return
\nfi<\/p>\n

PS1='h:W u d [t]<\/font>$ '
\n# Make bash check its window size after a process completes
\nshopt -s checkwinsize
\n# Tell the terminal about the working directory at each prompt.
\nif [ \"$TERM_PROGRAM\" == \"Apple_Terminal\" ] && [ -z \"$INSIDE_EMACS\" ]; then
\n update_terminal_cwd() {
\n # Identify the directory using a \"file:\" scheme URL,
\n # including the host name to disambiguate local vs.
\n # remote connections. Percent-escape spaces.
\n\tlocal SEARCH=' '
\n\tlocal REPLACE='%20'
\n\tlocal PWD_URL=\"file:\/\/$HOSTNAME${PWD\/\/$SEARCH\/$REPLACE}\"
\n\tprintf 'e]7;%sa' \"$PWD_URL\"
\n }
\n PROMPT_COMMAND=\"update_terminal_cwd; $PROMPT_COMMAND\"
\nfi<\/p>\n

<\/code><\/p>\n

If this was interesting you may be interested in this<\/a> too.<\/p>\n