| Symbol
|
Description
|
|
BASH_ENV |
The pathname of
the startup file for noninteractive shells |
|
COLUMNS |
The width of the
display used by select |
|
FCEDIT |
The name of the
editor that fc uses by default |
|
HISTFILE |
The pathname of
the file that holds the history list (default: ~.bash_history)
(this variable stores most recently executed commands.) |
|
HISTFILESIZE |
The maximum number
of entries saved in HISTFILE (default: 500) |
|
HISTSIZE |
The maximum number
of entries saved in HISTFILE (default: 500)
Example:
|
|
HOME |
Home directory |
|
PATH |
Where shell looks
for programs. (each directory must be separated from the next
by a colon)
Examples:
|
[bash]$
export PATH=/usr/local/bin:/bin:/usr/bin:~/bin:
#Exporting PATH makes it value accessible to sub-shells |
|
[bash]$
PATH=$PATH:/sbin #adds a /sbin directory
as the last directory to be searched in your current path
|
|
|
MAIL |
Where your mail
is Kept |
|
PROMPT_COMMAND |
A command that
bash executes just before it displays the primary prompt |
|
PS1 |
User Prompt (Primary)
Options:
Formating
Characters for PROMPT: (RedHat default prompt is [\u@\h\W]\$)
\! number of current
command in command history
\# number of the
command in the current session
\d date
\h hostname
\n newline
\s shell name
\t time
\u username
\w entire path
of working directory
\W only working
directory
Example:
|
[bash]$
PS1=”[\u@\h \w] Hello \$”;
|
|
|
PS2 |
User Prompt (Secondary).
It is a secondary environmental variable. It shows up on continuation
lines of command that are longer that one line |
|
PS3 |
Menu Prompt |
|
PS4 |
Debugging Prompt |
|
IFS |
Separates input
Fields (World Splitting) # Internal Field Separator
Example:
|
[bash]$
a=w:x:z
[bash]$
cat $a
[bash]$
cat: w:x:z No such file or directory # Interprets
the string w:x:z as a single world to be used as the argument
to cat
[bash]$
IFS=”:” # IFS is set to a colon (:)
[bash]$
cat $a # shell expands the variable a into
tree worlds, each of which is an argument to cat.
[bash]$
cat: w: No such file or directory
[bash]$
cat: x: No such file or directory
[bash]$
cat: z: No such file or directory
[bash]$
IFS=' \t\n' #IFS
default value |
|
|
INPUTRC |
The path name of
the Readline startup file (default: ~/.inputrc) |
|
LANG |
The locate category
when that category is not specifically set with an LC_* variable |
|
LC_* |
A group of variables
that specify locate categories including LC_COLLATE, LC_CTYPE,
LC_MESSAGES. And LC_NUMERIC; use the locate builtin
to display a complete list with values |
|
LINES |
The height of display
used by select |
|
LOGNAME |
Self
explanatory |
|
CDPATH |
The cd search path
# if you have several directories you like to work out of,
this variable can speed things up
Example:
|
[bash]$
export CDPATH=$HOME\:$HOME/school
# the commands cause cd command
to search home, school directories and then the working
directory |
|
[bash]$
CDPATH=~:/mnt/floppy/media:/mnt/cdrom
#sets a search path with CDPATH variable. |
|
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