Two important files under DOS are AUTOEXEC.BAT and CONFIG.SYS,
which are used at boot time to initialise the system, set some environment
variables like PATH and FILES, and possibly launch a program or batch file.
Under Linux there are several initialisation files, some of which you had
better not tamper with until you know exactly what you are doing. I'll tell
you what the most important are, anyway:
FILES NOTES
/etc/inittab don't touch for now!
/etc/rc.d/* ditto
If all you need is setting the $PATH and other environment
variables, or you want to change the login messages or automatically launch
a program after the login, have a look at the following files:
FILES NOTES
/etc/issue sets pre-login message
/etc/motd sets post-login message
/etc/profile sets $PATH and other variables, etc.
/etc/bashrc sets aliases and functions, etc.
/home/your_home/.bashrc sets your aliases + functions
/home/your_home/.bash_profile or
/home/your_home/.profile sets environment + starts your progs
If the latter file exists (note that it is a hidden file), it will be read after the login and the commands in it will be executed.
Example---look at this .bash_profile:
# I am a comment
echo Environment:
printenv | less # equivalent of command SET under DOS
alias d='ls -l' # easy to understand what an alias is
alias up='cd ..'
echo "I remind you that the path is "$PATH
echo "Today is `date`" # use the output of command 'date'
echo "Have a good day, "$LOGNAME
# The following is a "shell function"
ctgz() # List the contents of a .tar.gz archive.
{
for file in $*
do
gzip -dc ${file} | tar tf -
done
}
# end of .profile
$PATH and $LOGNAME, you guessed right, are
environment variables. There are many others to play with; for instance, RMP
for apps like less or bash.
Under Linux, virtually everything can be tailored to your needs. Most
programs have one or more initialisation files you can fiddle with, often as
a .prognamerc in your home dir. The first ones you'll want to modify
are:
.inputrc: used by bash to define keybindings;
.xinitrc: used by startx to initialise X Window System;
.fvwmrc: used by the window manager fvwm. A sample is in:
/usr/lib/X11/fvwm/system.fvwmrc;
.Xdefault: used by rxvt, a terminal emulator for X, and
other programs.
For all of these and the others you'll come across sooner or later, RMP.