bash: Bash Variables
1
1 5.2 Bash Variables
1 ==================
1
1 These variables are set or used by Bash, but other shells do not
1 normally treat them specially.
1
1 A few variables used by Bash are described in different chapters:
11 variables for controlling the job control facilities (⇒Job Control
Variables).
1
1 'BASH'
1 The full pathname used to execute the current instance of Bash.
1
1 'BASHOPTS'
1 A colon-separated list of enabled shell options. Each word in the
1 list is a valid argument for the '-s' option to the 'shopt' builtin
1 command (⇒The Shopt Builtin). The options appearing in
1 'BASHOPTS' are those reported as 'on' by 'shopt'. If this variable
1 is in the environment when Bash starts up, each shell option in the
1 list will be enabled before reading any startup files. This
1 variable is readonly.
1
1 'BASHPID'
1 Expands to the process ID of the current Bash process. This
1 differs from '$$' under certain circumstances, such as subshells
1 that do not require Bash to be re-initialized.
1
1 'BASH_ALIASES'
1 An associative array variable whose members correspond to the
1 internal list of aliases as maintained by the 'alias' builtin.
1 (⇒Bourne Shell Builtins). Elements added to this array
1 appear in the alias list; however, unsetting array elements
1 currently does not cause aliases to be removed from the alias list.
1 If 'BASH_ALIASES' is unset, it loses its special properties, even
1 if it is subsequently reset.
1
1 'BASH_ARGC'
1 An array variable whose values are the number of parameters in each
1 frame of the current bash execution call stack. The number of
1 parameters to the current subroutine (shell function or script
1 executed with '.' or 'source') is at the top of the stack. When a
1 subroutine is executed, the number of parameters passed is pushed
1 onto 'BASH_ARGC'. The shell sets 'BASH_ARGC' only when in extended
1 debugging mode (see ⇒The Shopt Builtin for a description of
1 the 'extdebug' option to the 'shopt' builtin).
1
1 'BASH_ARGV'
1 An array variable containing all of the parameters in the current
1 bash execution call stack. The final parameter of the last
1 subroutine call is at the top of the stack; the first parameter of
1 the initial call is at the bottom. When a subroutine is executed,
1 the parameters supplied are pushed onto 'BASH_ARGV'. The shell
1 The Shopt Builtin:: for a description of the 'extdebug' option to
1 the 'shopt' builtin).
1
1 'BASH_CMDS'
1 An associative array variable whose members correspond to the
1 internal hash table of commands as maintained by the 'hash' builtin
1 (⇒Bourne Shell Builtins). Elements added to this array
1 appear in the hash table; however, unsetting array elements
1 currently does not cause command names to be removed from the hash
1 table. If 'BASH_CMDS' is unset, it loses its special properties,
1 even if it is subsequently reset.
1
1 'BASH_COMMAND'
1 The command currently being executed or about to be executed,
1 unless the shell is executing a command as the result of a trap, in
1 which case it is the command executing at the time of the trap.
1
1 'BASH_COMPAT'
11 The value is used to set the shell's compatibility level. ⇒
The Shopt Builtin, for a description of the various compatibility
1 levels and their effects. The value may be a decimal number (e.g.,
1 4.2) or an integer (e.g., 42) corresponding to the desired
1 compatibility level. If 'BASH_COMPAT' is unset or set to the empty
1 string, the compatibility level is set to the default for the
1 current version. If 'BASH_COMPAT' is set to a value that is not
1 one of the valid compatibility levels, the shell prints an error
1 message and sets the compatibility level to the default for the
1 current version. The valid compatibility levels correspond to the
1 compatibility options accepted by the 'shopt' builtin described
1 above (for example, COMPAT42 means that 4.2 and 42 are valid
1 values). The current version is also a valid value.
1
1 'BASH_ENV'
1 If this variable is set when Bash is invoked to execute a shell
1 script, its value is expanded and used as the name of a startup
11 file to read before executing the script. ⇒Bash Startup
Files.
1
1 'BASH_EXECUTION_STRING'
1 The command argument to the '-c' invocation option.
1
1 'BASH_LINENO'
1 An array variable whose members are the line numbers in source
1 files where each corresponding member of FUNCNAME was invoked.
1 '${BASH_LINENO[$i]}' is the line number in the source file
1 ('${BASH_SOURCE[$i+1]}') where '${FUNCNAME[$i]}' was called (or
1 '${BASH_LINENO[$i-1]}' if referenced within another shell
1 function). Use 'LINENO' to obtain the current line number.
1
1 'BASH_LOADABLES_PATH'
1 A colon-separated list of directories in which the shell looks for
1 dynamically loadable builtins specified by the 'enable' command.
1
1 'BASH_REMATCH'
1 An array variable whose members are assigned by the '=~' binary
11 operator to the '[[' conditional command (⇒Conditional
Constructs). The element with index 0 is the portion of the
1 string matching the entire regular expression. The element with
1 index N is the portion of the string matching the Nth parenthesized
1 subexpression. This variable is read-only.
1
1 'BASH_SOURCE'
1 An array variable whose members are the source filenames where the
1 corresponding shell function names in the 'FUNCNAME' array variable
1 are defined. The shell function '${FUNCNAME[$i]}' is defined in
1 the file '${BASH_SOURCE[$i]}' and called from
1 '${BASH_SOURCE[$i+1]}'
1
1 'BASH_SUBSHELL'
1 Incremented by one within each subshell or subshell environment
1 when the shell begins executing in that environment. The initial
1 value is 0.
1
1 'BASH_VERSINFO'
1 A readonly array variable (⇒Arrays) whose members hold
1 version information for this instance of Bash. The values assigned
1 to the array members are as follows:
1
1 'BASH_VERSINFO[0]'
1 The major version number (the RELEASE).
1
1 'BASH_VERSINFO[1]'
1 The minor version number (the VERSION).
1
1 'BASH_VERSINFO[2]'
1 The patch level.
1
1 'BASH_VERSINFO[3]'
1 The build version.
1
1 'BASH_VERSINFO[4]'
1 The release status (e.g., BETA1).
1
1 'BASH_VERSINFO[5]'
1 The value of 'MACHTYPE'.
1
1 'BASH_VERSION'
1 The version number of the current instance of Bash.
1
1 'BASH_XTRACEFD'
1 If set to an integer corresponding to a valid file descriptor, Bash
1 will write the trace output generated when 'set -x' is enabled to
1 that file descriptor. This allows tracing output to be separated
1 from diagnostic and error messages. The file descriptor is closed
1 when 'BASH_XTRACEFD' is unset or assigned a new value. Unsetting
1 'BASH_XTRACEFD' or assigning it the empty string causes the trace
1 output to be sent to the standard error. Note that setting
1 'BASH_XTRACEFD' to 2 (the standard error file descriptor) and then
1 unsetting it will result in the standard error being closed.
1
1 'CHILD_MAX'
1 Set the number of exited child status values for the shell to
1 remember. Bash will not allow this value to be decreased below a
1 POSIX-mandated minimum, and there is a maximum value (currently
1 8192) that this may not exceed. The minimum value is
1 system-dependent.
1
1 'COLUMNS'
1 Used by the 'select' command to determine the terminal width when
1 printing selection lists. Automatically set if the 'checkwinsize'
1 option is enabled (⇒The Shopt Builtin), or in an interactive
1 shell upon receipt of a 'SIGWINCH'.
1
1 'COMP_CWORD'
1 An index into '${COMP_WORDS}' of the word containing the current
1 cursor position. This variable is available only in shell
11 functions invoked by the programmable completion facilities (⇒
Programmable Completion).
1
1 'COMP_LINE'
1 The current command line. This variable is available only in shell
1 functions and external commands invoked by the programmable
1 completion facilities (⇒Programmable Completion).
1
1 'COMP_POINT'
1 The index of the current cursor position relative to the beginning
1 of the current command. If the current cursor position is at the
1 end of the current command, the value of this variable is equal to
1 '${#COMP_LINE}'. This variable is available only in shell
1 functions and external commands invoked by the programmable
1 completion facilities (⇒Programmable Completion).
1
1 'COMP_TYPE'
1 Set to an integer value corresponding to the type of completion
1 attempted that caused a completion function to be called: TAB, for
1 normal completion, '?', for listing completions after successive
1 tabs, '!', for listing alternatives on partial word completion,
1 '@', to list completions if the word is not unmodified, or '%', for
1 menu completion. This variable is available only in shell
1 functions and external commands invoked by the programmable
1 completion facilities (⇒Programmable Completion).
1
1 'COMP_KEY'
1 The key (or final key of a key sequence) used to invoke the current
1 completion function.
1
1 'COMP_WORDBREAKS'
1 The set of characters that the Readline library treats as word
1 separators when performing word completion. If 'COMP_WORDBREAKS'
1 is unset, it loses its special properties, even if it is
1 subsequently reset.
1
1 'COMP_WORDS'
1 An array variable consisting of the individual words in the current
1 command line. The line is split into words as Readline would split
1 it, using 'COMP_WORDBREAKS' as described above. This variable is
1 available only in shell functions invoked by the programmable
1 completion facilities (⇒Programmable Completion).
1
1 'COMPREPLY'
1 An array variable from which Bash reads the possible completions
1 generated by a shell function invoked by the programmable
1 completion facility (⇒Programmable Completion). Each array
1 element contains one possible completion.
1
1 'COPROC'
1 An array variable created to hold the file descriptors for output
1 from and input to an unnamed coprocess (⇒Coprocesses).
1
1 'DIRSTACK'
1 An array variable containing the current contents of the directory
1 stack. Directories appear in the stack in the order they are
1 displayed by the 'dirs' builtin. Assigning to members of this
1 array variable may be used to modify directories already in the
1 stack, but the 'pushd' and 'popd' builtins must be used to add and
1 remove directories. Assignment to this variable will not change
1 the current directory. If 'DIRSTACK' is unset, it loses its
1 special properties, even if it is subsequently reset.
1
1 'EMACS'
1 If Bash finds this variable in the environment when the shell
1 starts with value 't', it assumes that the shell is running in an
1 Emacs shell buffer and disables line editing.
1
1 'ENV'
1 Similar to 'BASH_ENV'; used when the shell is invoked in POSIX Mode
1 (⇒Bash POSIX Mode).
1
1 'EUID'
1 The numeric effective user id of the current user. This variable
1 is readonly.
1
1 'EXECIGNORE'
1 A colon-separated list of shell patterns (⇒Pattern Matching)
1 defining the list of filenames to be ignored by command search
1 using 'PATH'. Files whose full pathnames match one of these
1 patterns are not considered executable files for the purposes of
1 completion and command execution via 'PATH' lookup. This does not
1 affect the behavior of the '[', 'test', and '[[' commands. Full
1 pathnames in the command hash table are not subject to
1 'EXECIGNORE'. Use this variable to ignore shared library files
1 that have the executable bit set, but are not executable files.
1 The pattern matching honors the setting of the 'extglob' shell
1 option.
1
1 'FCEDIT'
1 The editor used as a default by the '-e' option to the 'fc' builtin
1 command.
1
1 'FIGNORE'
1 A colon-separated list of suffixes to ignore when performing
1 filename completion. A filename whose suffix matches one of the
1 entries in 'FIGNORE' is excluded from the list of matched
1 filenames. A sample value is '.o:~'
1
1 'FUNCNAME'
1 An array variable containing the names of all shell functions
1 currently in the execution call stack. The element with index 0 is
1 the name of any currently-executing shell function. The
1 bottom-most element (the one with the highest index) is '"main"'.
1 This variable exists only when a shell function is executing.
1 Assignments to 'FUNCNAME' have no effect. If 'FUNCNAME' is unset,
1 it loses its special properties, even if it is subsequently reset.
1
1 This variable can be used with 'BASH_LINENO' and 'BASH_SOURCE'.
1 Each element of 'FUNCNAME' has corresponding elements in
1 'BASH_LINENO' and 'BASH_SOURCE' to describe the call stack. For
1 instance, '${FUNCNAME[$i]}' was called from the file
1 '${BASH_SOURCE[$i+1]}' at line number '${BASH_LINENO[$i]}'. The
1 'caller' builtin displays the current call stack using this
1 information.
1
1 'FUNCNEST'
1 If set to a numeric value greater than 0, defines a maximum
1 function nesting level. Function invocations that exceed this
1 nesting level will cause the current command to abort.
1
1 'GLOBIGNORE'
1 A colon-separated list of patterns defining the set of filenames to
1 be ignored by filename expansion. If a filename matched by a
1 filename expansion pattern also matches one of the patterns in
1 'GLOBIGNORE', it is removed from the list of matches. The pattern
1 matching honors the setting of the 'extglob' shell option.
1
1 'GROUPS'
1 An array variable containing the list of groups of which the
1 current user is a member. Assignments to 'GROUPS' have no effect.
1 If 'GROUPS' is unset, it loses its special properties, even if it
1 is subsequently reset.
1
1 'histchars'
1 Up to three characters which control history expansion, quick
1 substitution, and tokenization (⇒History Interaction). The
1 first character is the HISTORY EXPANSION character, that is, the
1 character which signifies the start of a history expansion,
1 normally '!'. The second character is the character which
1 signifies 'quick substitution' when seen as the first character on
1 a line, normally '^'. The optional third character is the
1 character which indicates that the remainder of the line is a
1 comment when found as the first character of a word, usually '#'.
1 The history comment character causes history substitution to be
1 skipped for the remaining words on the line. It does not
1 necessarily cause the shell parser to treat the rest of the line as
1 a comment.
1
1 'HISTCMD'
1 The history number, or index in the history list, of the current
1 command. If 'HISTCMD' is unset, it loses its special properties,
1 even if it is subsequently reset.
1
1 'HISTCONTROL'
1 A colon-separated list of values controlling how commands are saved
1 on the history list. If the list of values includes 'ignorespace',
1 lines which begin with a space character are not saved in the
1 history list. A value of 'ignoredups' causes lines which match the
1 previous history entry to not be saved. A value of 'ignoreboth' is
1 shorthand for 'ignorespace' and 'ignoredups'. A value of
1 'erasedups' causes all previous lines matching the current line to
1 be removed from the history list before that line is saved. Any
1 value not in the above list is ignored. If 'HISTCONTROL' is unset,
1 or does not include a valid value, all lines read by the shell
1 parser are saved on the history list, subject to the value of
1 'HISTIGNORE'. The second and subsequent lines of a multi-line
1 compound command are not tested, and are added to the history
1 regardless of the value of 'HISTCONTROL'.
1
1 'HISTFILE'
1 The name of the file to which the command history is saved. The
1 default value is '~/.bash_history'.
1
1 'HISTFILESIZE'
1 The maximum number of lines contained in the history file. When
1 this variable is assigned a value, the history file is truncated,
1 if necessary, to contain no more than that number of lines by
1 removing the oldest entries. The history file is also truncated to
1 this size after writing it when a shell exits. If the value is 0,
1 the history file is truncated to zero size. Non-numeric values and
1 numeric values less than zero inhibit truncation. The shell sets
1 the default value to the value of 'HISTSIZE' after reading any
1 startup files.
1
1 'HISTIGNORE'
1 A colon-separated list of patterns used to decide which command
1 lines should be saved on the history list. Each pattern is
1 anchored at the beginning of the line and must match the complete
1 line (no implicit '*' is appended). Each pattern is tested against
1 the line after the checks specified by 'HISTCONTROL' are applied.
1 In addition to the normal shell pattern matching characters, '&'
1 matches the previous history line. '&' may be escaped using a
1 backslash; the backslash is removed before attempting a match. The
1 second and subsequent lines of a multi-line compound command are
1 not tested, and are added to the history regardless of the value of
1 'HISTIGNORE'. The pattern matching honors the setting of the
1 'extglob' shell option.
1
1 'HISTIGNORE' subsumes the function of 'HISTCONTROL'. A pattern of
1 '&' is identical to 'ignoredups', and a pattern of '[ ]*' is
1 identical to 'ignorespace'. Combining these two patterns,
1 separating them with a colon, provides the functionality of
1 'ignoreboth'.
1
1 'HISTSIZE'
1 The maximum number of commands to remember on the history list. If
1 the value is 0, commands are not saved in the history list.
1 Numeric values less than zero result in every command being saved
1 on the history list (there is no limit). The shell sets the
1 default value to 500 after reading any startup files.
1
1 'HISTTIMEFORMAT'
1 If this variable is set and not null, its value is used as a format
1 string for STRFTIME to print the time stamp associated with each
1 history entry displayed by the 'history' builtin. If this variable
1 is set, time stamps are written to the history file so they may be
1 preserved across shell sessions. This uses the history comment
1 character to distinguish timestamps from other history lines.
1
1 'HOSTFILE'
1 Contains the name of a file in the same format as '/etc/hosts' that
1 should be read when the shell needs to complete a hostname. The
1 list of possible hostname completions may be changed while the
1 shell is running; the next time hostname completion is attempted
1 after the value is changed, Bash adds the contents of the new file
1 to the existing list. If 'HOSTFILE' is set, but has no value, or
1 does not name a readable file, Bash attempts to read '/etc/hosts'
1 to obtain the list of possible hostname completions. When
1 'HOSTFILE' is unset, the hostname list is cleared.
1
1 'HOSTNAME'
1 The name of the current host.
1
1 'HOSTTYPE'
1 A string describing the machine Bash is running on.
1
1 'IGNOREEOF'
1 Controls the action of the shell on receipt of an 'EOF' character
1 as the sole input. If set, the value denotes the number of
1 consecutive 'EOF' characters that can be read as the first
1 character on an input line before the shell will exit. If the
1 variable exists but does not have a numeric value (or has no value)
1 then the default is 10. If the variable does not exist, then 'EOF'
1 signifies the end of input to the shell. This is only in effect
1 for interactive shells.
1
1 'INPUTRC'
1 The name of the Readline initialization file, overriding the
1 default of '~/.inputrc'.
1
1 'LANG'
1 Used to determine the locale category for any category not
1 specifically selected with a variable starting with 'LC_'.
1
1 'LC_ALL'
1 This variable overrides the value of 'LANG' and any other 'LC_'
1 variable specifying a locale category.
1
1 'LC_COLLATE'
1 This variable determines the collation order used when sorting the
1 results of filename expansion, and determines the behavior of range
1 expressions, equivalence classes, and collating sequences within
11 filename expansion and pattern matching (⇒Filename
Expansion).
1
1 'LC_CTYPE'
1 This variable determines the interpretation of characters and the
1 behavior of character classes within filename expansion and pattern
1 matching (⇒Filename Expansion).
1
1 'LC_MESSAGES'
1 This variable determines the locale used to translate double-quoted
1 strings preceded by a '$' (⇒Locale Translation).
1
1 'LC_NUMERIC'
1 This variable determines the locale category used for number
1 formatting.
1
1 'LC_TIME'
1 This variable determines the locale category used for data and time
1 formatting.
1
1 'LINENO'
1 The line number in the script or shell function currently
1 executing.
1
1 'LINES'
1 Used by the 'select' command to determine the column length for
1 printing selection lists. Automatically set if the 'checkwinsize'
1 option is enabled (⇒The Shopt Builtin), or in an interactive
1 shell upon receipt of a 'SIGWINCH'.
1
1 'MACHTYPE'
1 A string that fully describes the system type on which Bash is
1 executing, in the standard GNU CPU-COMPANY-SYSTEM format.
1
1 'MAILCHECK'
1 How often (in seconds) that the shell should check for mail in the
1 files specified in the 'MAILPATH' or 'MAIL' variables. The default
1 is 60 seconds. When it is time to check for mail, the shell does
1 so before displaying the primary prompt. If this variable is
1 unset, or set to a value that is not a number greater than or equal
1 to zero, the shell disables mail checking.
1
1 'MAPFILE'
1 An array variable created to hold the text read by the 'mapfile'
1 builtin when no variable name is supplied.
1
1 'OLDPWD'
1 The previous working directory as set by the 'cd' builtin.
1
1 'OPTERR'
1 If set to the value 1, Bash displays error messages generated by
1 the 'getopts' builtin command.
1
1 'OSTYPE'
1 A string describing the operating system Bash is running on.
1
1 'PIPESTATUS'
1 An array variable (⇒Arrays) containing a list of exit status
1 values from the processes in the most-recently-executed foreground
1 pipeline (which may contain only a single command).
1
1 'POSIXLY_CORRECT'
1 If this variable is in the environment when Bash starts, the shell
1 enters POSIX mode (⇒Bash POSIX Mode) before reading the
1 startup files, as if the '--posix' invocation option had been
1 supplied. If it is set while the shell is running, Bash enables
1 POSIX mode, as if the command
1 set -o posix
1 had been executed.
1
1 'PPID'
1 The process ID of the shell's parent process. This variable is
1 readonly.
1
1 'PROMPT_COMMAND'
1 If set, the value is interpreted as a command to execute before the
1 printing of each primary prompt ('$PS1').
1
1 'PROMPT_DIRTRIM'
1 If set to a number greater than zero, the value is used as the
1 number of trailing directory components to retain when expanding
11 the '\w' and '\W' prompt string escapes (⇒Controlling the
Prompt). Characters removed are replaced with an ellipsis.
1
1 'PS0'
1 The value of this parameter is expanded like PS1 and displayed by
1 interactive shells after reading a command and before the command
1 is executed.
1
1 'PS3'
1 The value of this variable is used as the prompt for the 'select'
1 command. If this variable is not set, the 'select' command prompts
1 with '#? '
1
1 'PS4'
1 The value is the prompt printed before the command line is echoed
1 when the '-x' option is set (⇒The Set Builtin). The first
1 character of 'PS4' is replicated multiple times, as necessary, to
1 indicate multiple levels of indirection. The default is '+ '.
1
1 'PWD'
1 The current working directory as set by the 'cd' builtin.
1
1 'RANDOM'
1 Each time this parameter is referenced, a random integer between 0
1 and 32767 is generated. Assigning a value to this variable seeds
1 the random number generator.
1
1 'READLINE_LINE'
1 The contents of the Readline line buffer, for use with 'bind -x'
1 (⇒Bash Builtins).
1
1 'READLINE_POINT'
1 The position of the insertion point in the Readline line buffer,
1 for use with 'bind -x' (⇒Bash Builtins).
1
1 'REPLY'
1 The default variable for the 'read' builtin.
1
1 'SECONDS'
1 This variable expands to the number of seconds since the shell was
1 started. Assignment to this variable resets the count to the value
1 assigned, and the expanded value becomes the value assigned plus
1 the number of seconds since the assignment.
1
1 'SHELL'
1 The full pathname to the shell is kept in this environment
1 variable. If it is not set when the shell starts, Bash assigns to
1 it the full pathname of the current user's login shell.
1
1 'SHELLOPTS'
1 A colon-separated list of enabled shell options. Each word in the
1 list is a valid argument for the '-o' option to the 'set' builtin
1 command (⇒The Set Builtin). The options appearing in
1 'SHELLOPTS' are those reported as 'on' by 'set -o'. If this
1 variable is in the environment when Bash starts up, each shell
1 option in the list will be enabled before reading any startup
1 files. This variable is readonly.
1
1 'SHLVL'
1 Incremented by one each time a new instance of Bash is started.
1 This is intended to be a count of how deeply your Bash shells are
1 nested.
1
1 'TIMEFORMAT'
1 The value of this parameter is used as a format string specifying
1 how the timing information for pipelines prefixed with the 'time'
1 reserved word should be displayed. The '%' character introduces an
1 escape sequence that is expanded to a time value or other
1 information. The escape sequences and their meanings are as
1 follows; the braces denote optional portions.
1
1 '%%'
1 A literal '%'.
1
1 '%[P][l]R'
1 The elapsed time in seconds.
1
1 '%[P][l]U'
1 The number of CPU seconds spent in user mode.
1
1 '%[P][l]S'
1 The number of CPU seconds spent in system mode.
1
1 '%P'
1 The CPU percentage, computed as (%U + %S) / %R.
1
1 The optional P is a digit specifying the precision, the number of
1 fractional digits after a decimal point. A value of 0 causes no
1 decimal point or fraction to be output. At most three places after
1 the decimal point may be specified; values of P greater than 3 are
1 changed to 3. If P is not specified, the value 3 is used.
1
1 The optional 'l' specifies a longer format, including minutes, of
1 the form MMmSS.FFs. The value of P determines whether or not the
1 fraction is included.
1
1 If this variable is not set, Bash acts as if it had the value
1 $'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'
1 If the value is null, no timing information is displayed. A
1 trailing newline is added when the format string is displayed.
1
1 'TMOUT'
1 If set to a value greater than zero, 'TMOUT' is treated as the
1 default timeout for the 'read' builtin (⇒Bash Builtins).
1 The 'select' command (⇒Conditional Constructs) terminates if
1 input does not arrive after 'TMOUT' seconds when input is coming
1 from a terminal.
1
1 In an interactive shell, the value is interpreted as the number of
1 seconds to wait for a line of input after issuing the primary
1 prompt. Bash terminates after waiting for that number of seconds
1 if a complete line of input does not arrive.
1
1 'TMPDIR'
1 If set, Bash uses its value as the name of a directory in which
1 Bash creates temporary files for the shell's use.
1
1 'UID'
1 The numeric real user id of the current user. This variable is
1 readonly.
1