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BASH Startup Files
The Bourne Again Shell uses several startup files.
/etc/profile a
system-wide startup file
a login initialization file composed one of the following
:
.bash_profile
.bash_login
.profile
Finally, bash looks in the home directory for the shell
initialization file.
.bashrc
After that, every interactive bash subshell executes the commands in .bashrc.
List the current settings of the environment variables.
This is done with the set command without arguments:
BASH > set
Some common environment variables.
|
Variable |
Contents |
| HOME |
Pathname of your home directory |
| MAIL |
Pathname of your system mailbox |
| PATH |
Directories where shell is to look for commands |
| PS1 |
Primary prompt |
| PS2 |
Secondary prompt |
| PWD |
Present working directory |
| SHELL |
Pathname of login shell (/usr/bin/bash
or /bin/bash ) |
| TERM |
The termcap code for your terminal |
| USER |
Your user name |
Setting the prompt.
PS1="Your Majesty?"
PS1= #
Commands for customizing prompt strings.
| Command |
Meaning |
| \a |
audible bell (ASCII code 007) |
| \d |
date in "Weekday Month Day" format |
| \e |
escape character (ASCII code 033) |
| \H |
Hostname (long) |
| \h |
hostname (short) |
| \n |
newline (carriage return followed by a line feed) |
| \s |
shell name |
| \T |
Time in 12-hour "HH:MM:SS" format |
| \t |
time in 24-hour "HH:MM:SS" format |
| \@ |
time in 12-hour "am/pm" format |
| \u |
user name |
| \V |
version of bash (long format) |
| \v |
version of bash (short format) |
| \W |
working directory |
| \w |
working directory |
| \# |
number of current command |
| \! |
history number of current command |
| \$ |
# for superuser (UID of 0); $ for otherwise |
| \\ |
backslash |
| \nnn |
ASCII character code (in octal) |
| \[ |
start if non-printing character sequence |
| \] |
end of non-printing character sequence |
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