bash.1

android-w.song.android.widget

.SM
.B BASH_XTRACEFD
to 2 (the standard error file
descriptor) and then unsetting it will result in the standard error
being closed.
.TP
.B CDPATH
The search path for the
.B cd
command.
This is a colon-separated list of directories in which the shell looks
for destination directories specified by the
.B cd
command.
A sample value is
.if t \f(CW".:~:/usr"\fP.
.if n ".:~:/usr".
.TP
.B COLUMNS
Used by the \fBselect\fP compound command to determine the terminal width
when printing selection lists.  Automatically set upon receipt of a
.SM
.BR SIGWINCH .
.TP
.B COMPREPLY
An array variable from which \fBbash\fP reads the possible completions
generated by a shell function invoked by the programmable completion
facility (see \fBProgrammable Completion\fP below).
.TP
.B EMACS
If \fBbash\fP finds this variable in the environment when the shell starts
with value
.if t \f(CWt\fP,
.if n "t",
it assumes that the shell is running in an Emacs shell buffer and disables
line editing.
.TP
.B ENV
Similar to
.SM
.BR BASH_ENV ;
used when the shell is invoked in POSIX mode.
.TP
.B FCEDIT
The default editor for the
.B fc
builtin command.
.TP
.B FIGNORE
A colon-separated list of suffixes to ignore when performing
filename completion (see
.SM
.B READLINE
below).
A filename whose suffix matches one of the entries in 
.SM
.B FIGNORE
is excluded from the list of matched filenames.
A sample value is
.if t \f(CW".o:~"\fP.
.if n ".o:~".
.TP
.B FUNCNEST
If set to a numeric value greater than 0, defines a maximum function
nesting level.  Function invocations that exceed this nesting level
will cause the current command to abort.
.TP
.B GLOBIGNORE
A colon-separated list of patterns defining the set of filenames to
be ignored by pathname expansion.
If a filename matched by a pathname expansion pattern also matches one
of the patterns in
.SM
.BR GLOBIGNORE ,
it is removed from the list of matches.
.TP
.B HISTCONTROL
A colon-separated list of values controlling how commands are saved on
the history list.
If the list of values includes
.IR ignorespace ,
lines which begin with a
.B space
character are not saved in the history list.
A value of 
.I ignoredups
causes lines matching the previous history entry to not be saved.
A value of
.I ignoreboth
is shorthand for \fIignorespace\fP and \fIignoredups\fP.
A value of
.IR erasedups
causes all previous lines matching the current line to be removed from
the history list before that line is saved.
Any value not in the above list is ignored.
If
.SM
.B HISTCONTROL
is unset, or does not include a valid value,
all lines read by the shell parser are saved on the history list,
subject to the value of
.SM
.BR HISTIGNORE .
The second and subsequent lines of a multi-line compound command are
not tested, and are added to the history regardless of the value of
.SM
.BR HISTCONTROL .
.TP
.B HISTFILE
The name of the file in which command history is saved (see
.SM
.B HISTORY
below).  The default value is \fI~/.bash_history\fP.  If unset, the
command history is not saved when an interactive shell exits.
.TP
.B HISTFILESIZE
The maximum number of lines contained in the history file.  When this
variable is assigned a value, the history file is truncated, if
necessary, by removing the oldest entries,
to contain no more than that number of lines.  The default
value is 500.  The history file is also truncated to this size after
writing it when an interactive shell exits.
.TP
.B HISTIGNORE
A colon-separated list of patterns used to decide which command lines
should be saved on the history list.  Each pattern is anchored at the
beginning of the line and must match the complete line (no implicit
`\fB*\fP' is appended).  Each pattern is tested against the line
after the checks specified by
.SM
.B HISTCONTROL
are applied.
In addition to the normal shell pattern matching characters, `\fB&\fP'
matches the previous history line.  `\fB&\fP' may be escaped using a
backslash; the backslash is removed before attempting a match.
The second and subsequent lines of a multi-line compound command are
not tested, and are added to the history regardless of the value of
.SM
.BR HISTIGNORE .
.TP
.B HISTSIZE
The number of commands to remember in the command history (see
.SM
.B HISTORY
below).  The default value is 500.
.TP
.B HISTTIMEFORMAT
If this variable is set and not null, its value is used as a format string
for \fIstrftime\fP(3) to print the time stamp associated with each history
entry displayed by the \fBhistory\fP builtin.
If this variable is set, time stamps are written to the history file so
they may be preserved across shell sessions.
This uses the history comment character to distinguish timestamps from
other history lines.
.TP
.B HOME
The home directory of the current user; the default argument for the
\fBcd\fP builtin command.
The value of this variable is also used when performing tilde expansion.
.TP
.B HOSTFILE
Contains the name of a file in the same format as
.FN /etc/hosts
that should be read when the shell needs to complete a
hostname.
The list of possible hostname completions may be changed while the
shell is running;
the next time hostname completion is attempted after the
value is changed,
.B bash
adds the contents of the new file to the existing list.
If
.SM
.B HOSTFILE
is set, but has no value, or does not name a readable file,
\fBbash\fP attempts to read
.FN /etc/hosts
to obtain the list of possible hostname completions.
When
.SM
.B HOSTFILE
is unset, the hostname list is cleared.
.TP
.B IFS
The
.I Internal Field Separator
that is used
for word splitting after expansion and to
split lines into words with the
.B read
builtin command.  The default value is
``<space><tab><newline>''.
.TP
.B IGNOREEOF
Controls the
action of an interactive shell on receipt of an
.SM
.B EOF
character as the sole input.  If set, the value is the number of
consecutive
.SM
.B EOF
characters which must be
typed as the first characters on an input line before
.B bash
exits.  If the variable exists but does not have a numeric value, or
has no value, the default value is 10.  If it does not exist,
.SM
.B EOF
signifies the end of input to the shell.
.TP
.B INPUTRC
The filename for the
.B readline
startup file, overriding the default of
.FN ~/.inputrc
(see
.SM
.B READLINE
below).
.TP
.B LANG
Used to determine the locale category for any category not specifically
selected with a variable starting with \fBLC_\fP.
.TP
.B LC_ALL
This variable overrides the value of
.SM
.B LANG
and any other
\fBLC_\fP variable specifying a locale category.
.TP
.B LC_COLLATE
This variable determines the collation order used when sorting the
results of pathname expansion, and determines the behavior of range
expressions, equivalence classes, and collating sequences within
pathname expansion and pattern matching.
.TP
.B LC_CTYPE
This variable determines the interpretation of characters and the
behavior of character classes within pathname expansion and pattern
matching.
.TP
.B LC_MESSAGES
This variable determines the locale used to translate double-quoted
strings preceded by a \fB$\fP.
.TP
.B LC_NUMERIC
This variable determines the locale category used for number formatting.
.TP
.B LINES
Used by the \fBselect\fP compound command to determine the column length
for printing selection lists.  Automatically set upon receipt of a
.SM
.BR SIGWINCH .
.TP
.B MAIL
If this parameter is set to a file or directory name and the
.SM
.B MAILPATH
variable is not set,
.B bash
informs the user of the arrival of mail in the specified file or
Maildir-format directory.
.TP
.B MAILCHECK
Specifies how
often (in seconds)
.B bash
checks for mail.  The default is 60 seconds.  When it is time to check
for mail, the shell does so before displaying the primary prompt.
If this variable is unset, or set to a value that is not a number
greater than or equal to zero, the shell disables mail checking.
.TP
.B MAILPATH
A colon-separated list of file names to be checked for mail. 
The message to be printed when mail arrives in a particular file
may be specified by separating the file name from the message with a `?'.
When used in the text of the message, \fB$_\fP expands to the name of
the current mailfile. 
Example:
.RS
.PP
\fBMAILPATH\fP=\(aq/var/mail/bfox?"You have mail":~/shell\-mail?"$_ has mail!"\(aq
.PP
.B Bash
supplies a default value for this variable, but the location of the user
mail files that it uses is system dependent (e.g., /var/mail/\fB$USER\fP).
.RE
.TP
.B OPTERR
If set to the value 1,
.B bash
displays error messages generated by the
.B getopts
builtin command (see
.SM
.B SHELL BUILTIN COMMANDS
below).
.SM
.B OPTERR
is initialized to 1 each time the shell is invoked or a shell
script is executed.
.TP
.B PATH
The search path for commands.  It
is a colon-separated list of directories in which
the shell looks for commands (see
.SM
.B COMMAND EXECUTION
below).
A zero-length (null) directory name in the value of
.SM
.B PATH
indicates the current directory.
A null directory name may appear as two adjacent colons, or as an initial
or trailing colon.
The default path is system-dependent,
and is set by the administrator who installs
.BR bash .
A common value is
.if t \f(CW/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin\fP.
.if n ``/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin''.
.TP
.B POSIXLY_CORRECT
If this variable is in the environment when \fBbash\fP starts, the shell
enters \fIposix mode\fP before reading the startup files, as if the
.B \-\-posix
invocation option had been supplied.  If it is set while the shell is
running, \fBbash\fP enables \fIposix mode\fP, as if the command
.if t \f(CWset -o posix\fP
.if n \fIset -o posix\fP
had been executed.
.TP
.B PROMPT_COMMAND
If set, the value is executed as a command prior to issuing each primary
prompt.
.TP
.B PROMPT_DIRTRIM
If set to a number greater than zero, the value is used as the number of
trailing directory components to retain when expanding the \fB\ew\fP and
\fB\eW\fP prompt string escapes (see
.SM
.B PROMPTING
below).  Characters removed are replaced with an ellipsis.
.TP
.B PS1
The value of this parameter is expanded (see
.SM
.B PROMPTING
below) and used as the primary prompt string.  The default value is
``\fB\es\-\ev\e$ \fP''.
.TP
.B PS2
The value of this parameter is expanded as with
.SM
.B PS1
and used as the secondary prompt string.  The default is
``\fB> \fP''.
.TP
.B PS3
The value of this parameter is used as the prompt for the
.B select
command (see
.SM
.B SHELL GRAMMAR
above).
.TP
.B PS4
The value of this parameter is expanded as with
.SM
.B PS1
and the value is printed before each command
.B bash
displays during an execution trace.  The first character of
.SM
.B PS4
is replicated multiple times, as necessary, to indicate multiple
levels of indirection.  The default is ``\fB+ \fP''.
.TP
.B SHELL
The full pathname to the shell is kept in this environment variable.
If it is not set when the shell starts,
.B bash
assigns to it the full pathname of the current user's login shell.
.TP
.B TIMEFORMAT
The value of this parameter is used as a format string specifying
how the timing information for pipelines prefixed with the
.B time
reserved word should be displayed.
The \fB%\fP character introduces an escape sequence that is
expanded to a time value or other information.
The escape sequences and their meanings are as follows; the
braces denote optional portions.
.sp .5
.RS
.PD 0
.TP 10
.B %%
A literal \fB%\fP.
.TP
.B %[\fIp\fP][l]R
The elapsed time in seconds.
.TP
.B %[\fIp\fP][l]U
The number of CPU seconds spent in user mode.
.TP
.B %[\fIp\fP][l]S
The number of CPU seconds spent in system mode.
.TP
.B %P
The CPU percentage, computed as (%U + %S) / %R.
.PD
.RE
.IP
The optional \fIp\fP is a digit specifying the \fIprecision\fP,
the number of fractional digits after a decimal point.
A value of 0 causes no decimal point or fraction to be output.
At most three places after the decimal point may be specified;
values of \fIp\fP greater than 3 are changed to 3.
If \fIp\fP is not specified, the value 3 is used.
.IP
The optional \fBl\fP specifies a longer format, including
minutes, of the form \fIMM\fPm\fISS\fP.\fIFF\fPs.
The value of \fIp\fP determines whether or not the fraction is
included.
.IP
If this variable is not set, \fBbash\fP acts as if it had the
value \fB$\(aq\enreal\et%3lR\enuser\et%3lU\ensys\t%3lS\(aq\fP.
If the value is null, no timing information is displayed.
A trailing newline is added when the format string is displayed.
.PD 0
.TP
.B TMOUT
If set to a value greater than zero,
.SM
.B TMOUT
is treated as the
default timeout for the \fBread\fP builtin.
The \fBselect\fP command terminates if input does not arrive
after
.SM
.B TMOUT
seconds when input is coming from a terminal.
In an interactive shell, the value is interpreted as the
number of seconds to wait for input after issuing the primary prompt.
.B Bash
terminates after waiting for that number of seconds if input does
not arrive.
.TP
.B TMPDIR
If set, \fBbash\fP uses its value as the name of a directory in which
\fBbash\fP creates temporary files for the shell's use.
.TP
.B auto_resume
This variable controls how the shell interacts with the user and
job control.  If this variable is set, single word simple
commands without redirections are treated as candidates fo