Translations by Andrej Znidarsic

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Set Readline key bindings and variables. Bind a key sequence to a Readline function or a macro, or set a Readline variable. The non-option argument syntax is equivalent to that found in ~/.inputrc, but must be passed as a single argument: e.g., bind '"\C-x\C-r": re-read-init-file'. Options: -m keymap Use KEYMAP as the keymap for the duration of this command. Acceptable keymap names are emacs, emacs-standard, emacs-meta, emacs-ctlx, vi, vi-move, vi-command, and vi-insert. -l List names of functions. -P List function names and bindings. -p List functions and bindings in a form that can be reused as input. -S List key sequences that invoke macros and their values -s List key sequences that invoke macros and their values in a form that can be reused as input. -V List variable names and values -v List variable names and values in a form that can be reused as input. -q function-name Query about which keys invoke the named function. -u function-name Unbind all keys which are bound to the named function. -r keyseq Remove the binding for KEYSEQ. -f filename Read key bindings from FILENAME. -x keyseq:shell-command Cause SHELL-COMMAND to be executed when KEYSEQ is entered. Exit Status: bind returns 0 unless an unrecognized option is given or an error occurs.

Exit for, while, or until loops. Exit a FOR, WHILE or UNTIL loop. If N is specified, break N enclosing loops. Exit Status: The exit status is 0 unless N is not greater than or equal to 1.

Resume for, while, or until loops. Resumes the next iteration of the enclosing FOR, WHILE or UNTIL loop. If N is specified, resumes the Nth enclosing loop. Exit Status: The exit status is 0 unless N is not greater than or equal to 1.

Change the shell working directory. Change the current directory to DIR. The default DIR is the value of the HOME shell variable. The variable CDPATH defines the search path for the directory containing DIR. Alternative directory names in CDPATH are separated by a colon (:). A null directory name is the same as the current directory. If DIR begins with a slash (/), then CDPATH is not used. If the directory is not found, and the shell option `cdable_vars' is set, the word is assumed to be a variable name. If that variable has a value, its value is used for DIR. Options: -L force symbolic links to be followed -P use the physical directory structure without following symbolic links -e if the -P option is supplied, and the current working directory cannot be determined successfully, exit with a non-zero status The default is to follow symbolic links, as if `-L' were specified. Exit Status: Returns 0 if the directory is changed, and if $PWD is set successfully when -P is used; non-zero otherwise.

Print the name of the current working directory. Options: -L print the value of $PWD if it names the current working directory -P print the physical directory, without any symbolic links By default, `pwd' behaves as if `-L' were specified. Exit Status: Returns 0 unless an invalid option is given or the current directory cannot be read.

Return a successful result. Exit Status: Always succeeds.

Return an unsuccessful result. Exit Status: Always fails.

Set variable values and attributes. Declare variables and give them attributes. If no NAMEs are given, display the attributes and values of all variables. Options: -f restrict action or display to function names and definitions -F restrict display to function names only (plus line number and source file when debugging) -g create global variables when used in a shell function; otherwise ignored -p display the attributes and value of each NAME Options which set attributes: -a to make NAMEs indexed arrays (if supported) -A to make NAMEs associative arrays (if supported) -i to make NAMEs have the `integer' attribute -l to convert NAMEs to lower case on assignment -r to make NAMEs readonly -t to make NAMEs have the `trace' attribute -u to convert NAMEs to upper case on assignment -x to make NAMEs export Using `+' instead of `-' turns off the given attribute. Variables with the integer attribute have arithmetic evaluation (see the `let' command) performed when the variable is assigned a value. When used in a function, `declare' makes NAMEs local, as with the `local' command. The `-g' option suppresses this behavior. Exit Status: Returns success unless an invalid option is supplied or an error occurs.

Set variable values and attributes. Obsolete. See `help declare'.

Define local variables. Create a local variable called NAME, and give it VALUE. OPTION can be any option accepted by `declare'. Local variables can only be used within a function; they are visible only to the function where they are defined and its children. Exit Status: Returns success unless an invalid option is supplied, an error occurs, or the shell is not executing a function.

Write arguments to the standard output. Display the ARGs on the standard output followed by a newline. Options: -n do not append a newline -e enable interpretation of the following backslash escapes -E explicitly suppress interpretation of backslash escapes `echo' interprets the following backslash-escaped characters: \a alert (bell) \b backspace \c suppress further output \e escape character \f form feed \n new line \r carriage return \t horizontal tab \v vertical tab \\ backslash \0nnn the character whose ASCII code is NNN (octal). NNN can be 0 to 3 octal digits \xHH the eight-bit character whose value is HH (hexadecimal). HH can be one or two hex digits Exit Status: Returns success unless a write error occurs.

Enable and disable shell builtins. Enables and disables builtin shell commands. Disabling allows you to execute a disk command which has the same name as a shell builtin without using a full pathname. Options: -a print a list of builtins showing whether or not each is enabled -n disable each NAME or display a list of disabled builtins -p print the list of builtins in a reusable format -s print only the names of Posix `special' builtins Options controlling dynamic loading: -f Load builtin NAME from shared object FILENAME -d Remove a builtin loaded with -f Without options, each NAME is enabled. To use the `test' found in $PATH instead of the shell builtin version, type `enable -n test'. Exit Status: Returns success unless NAME is not a shell builtin or an error occurs.

Parse option arguments. Getopts is used by shell procedures to parse positional parameters as options. OPTSTRING contains the option letters to be recognized; if a letter is followed by a colon, the option is expected to have an argument, which should be separated from it by white space. Each time it is invoked, getopts will place the next option in the shell variable $name, initializing name if it does not exist, and the index of the next argument to be processed into the shell variable OPTIND. OPTIND is initialized to 1 each time the shell or a shell script is invoked. When an option requires an argument, getopts places that argument into the shell variable OPTARG. getopts reports errors in one of two ways. If the first character of OPTSTRING is a colon, getopts uses silent error reporting. In this mode, no error messages are printed. If an invalid option is seen, getopts places the option character found into OPTARG. If a required argument is not found, getopts places a ':' into NAME and sets OPTARG to the option character found. If getopts is not in silent mode, and an invalid option is seen, getopts places '?' into NAME and unsets OPTARG. If a required argument is not found, a '?' is placed in NAME, OPTARG is unset, and a diagnostic message is printed. If the shell variable OPTERR has the value 0, getopts disables the printing of error messages, even if the first character of OPTSTRING is not a colon. OPTERR has the value 1 by default. Getopts normally parses the positional parameters ($0 - $9), but if more arguments are given, they are parsed instead. Exit Status: Returns success if an option is found; fails if the end of options is encountered or an error occurs.

Display or execute commands from the history list. fc is used to list or edit and re-execute commands from the history list. FIRST and LAST can be numbers specifying the range, or FIRST can be a string, which means the most recent command beginning with that string. Options: -e ENAME select which editor to use. Default is FCEDIT, then EDITOR, then vi -l list lines instead of editing -n omit line numbers when listing -r reverse the order of the lines (newest listed first) With the `fc -s [pat=rep ...] [command]' format, COMMAND is re-executed after the substitution OLD=NEW is performed. A useful alias to use with this is r='fc -s', so that typing `r cc' runs the last command beginning with `cc' and typing `r' re-executes the last command. Exit Status: Returns success or status of executed command; non-zero if an error occurs.

Move job to the foreground. Place the job identified by JOB_SPEC in the foreground, making it the current job. If JOB_SPEC is not present, the shell's notion of the current job is used. Exit Status: Status of command placed in foreground, or failure if an error occurs.

Move jobs to the background. Place the jobs identified by each JOB_SPEC in the background, as if they had been started with `&'. If JOB_SPEC is not present, the shell's notion of the current job is used. Exit Status: Returns success unless job control is not enabled or an error occurs.

Display information about builtin commands. Displays brief summaries of builtin commands. If PATTERN is specified, gives detailed help on all commands matching PATTERN, otherwise the list of help topics is printed. Options: -d output short description for each topic -m display usage in pseudo-manpage format -s output only a short usage synopsis for each topic matching PATTERN Arguments: PATTERN Pattern specifiying a help topic Exit Status: Returns success unless PATTERN is not found or an invalid option is given.

Display or manipulate the history list. Display the history list with line numbers, prefixing each modified entry with a `*'. An argument of N lists only the last N entries. Options: -c clear the history list by deleting all of the entries -d offset delete the history entry at offset OFFSET. -a append history lines from this session to the history file -n read all history lines not already read from the history file -r read the history file and append the contents to the history list -w write the current history to the history file and append them to the history list -p perform history expansion on each ARG and display the result without storing it in the history list -s append the ARGs to the history list as a single entry If FILENAME is given, it is used as the history file. Otherwise, if $HISTFILE has a value, that is used, else ~/.bash_history. If the $HISTTIMEFORMAT variable is set and not null, its value is used as a format string for strftime(3) to print the time stamp associated with each displayed history entry. No time stamps are printed otherwise. Exit Status: Returns success unless an invalid option is given or an error occurs.

Evaluate arithmetic expressions. Evaluate each ARG as an arithmetic expression. Evaluation is done in fixed-width integers with no check for overflow, though division by 0 is trapped and flagged as an error. The following list of operators is grouped into levels of equal-precedence operators. The levels are listed in order of decreasing precedence. id++, id-- variable post-increment, post-decrement ++id, --id variable pre-increment, pre-decrement -, + unary minus, plus !, ~ logical and bitwise negation ** exponentiation *, /, % multiplication, division, remainder +, - addition, subtraction <<, >> left and right bitwise shifts <=, >=, <, > comparison ==, != equality, inequality & bitwise AND ^ bitwise XOR | bitwise OR && logical AND || logical OR expr ? expr : expr conditional operator =, *=, /=, %=, +=, -=, <<=, >>=, &=, ^=, |= assignment Shell variables are allowed as operands. The name of the variable is replaced by its value (coerced to a fixed-width integer) within an expression. The variable need not have its integer attribute turned on to be used in an expression. Operators are evaluated in order of precedence. Sub-expressions in parentheses are evaluated first and may override the precedence rules above. Exit Status: If the last ARG evaluates to 0, let returns 1; let returns 0 otherwise.

Read a line from the standard input and split it into fields. Reads a single line from the standard input, or from file descriptor FD if the -u option is supplied. The line is split into fields as with word splitting, and the first word is assigned to the first NAME, the second word to the second NAME, and so on, with any leftover words assigned to the last NAME. Only the characters found in $IFS are recognized as word delimiters. If no NAMEs are supplied, the line read is stored in the REPLY variable. Options: -a array assign the words read to sequential indices of the array variable ARRAY, starting at zero -d delim continue until the first character of DELIM is read, rather than newline -e use Readline to obtain the line in an interactive shell -i text Use TEXT as the initial text for Readline -n nchars return after reading NCHARS characters rather than waiting for a newline, but honor a delimiter if fewer than NCHARS characters are read before the delimiter -N nchars return only after reading exactly NCHARS characters, unless EOF is encountered or read times out, ignoring any delimiter -p prompt output the string PROMPT without a trailing newline before attempting to read -r do not allow backslashes to escape any characters -s do not echo input coming from a terminal -t timeout time out and return failure if a complete line of input is not read withint TIMEOUT seconds. The value of the TMOUT variable is the default timeout. TIMEOUT may be a fractional number. If TIMEOUT is 0, read returns success only if input is available on the specified file descriptor. The exit status is greater than 128 if the timeout is exceeded -u fd read from file descriptor FD instead of the standard input Exit Status: The return code is zero, unless end-of-file is encountered, read times out, or an invalid file descriptor is supplied as the argument to -u.

Return from a shell function. Causes a function or sourced script to exit with the return value specified by N. If N is omitted, the return status is that of the last command executed within the function or script. Exit Status: Returns N, or failure if the shell is not executing a function or script.

Set or unset values of shell options and positional parameters. Change the value of shell attributes and positional parameters, or display the names and values of shell variables. Options: -a Mark variables which are modified or created for export. -b Notify of job termination immediately. -e Exit immediately if a command exits with a non-zero status. -f Disable file name generation (globbing). -h Remember the location of commands as they are looked up. -k All assignment arguments are placed in the environment for a command, not just those that precede the command name. -m Job control is enabled. -n Read commands but do not execute them. -o option-name Set the variable corresponding to option-name: allexport same as -a braceexpand same as -B emacs use an emacs-style line editing interface errexit same as -e errtrace same as -E functrace same as -T hashall same as -h histexpand same as -H history enable command history ignoreeof the shell will not exit upon reading EOF interactive-comments allow comments to appear in interactive commands keyword same as -k monitor same as -m noclobber same as -C noexec same as -n noglob same as -f nolog currently accepted but ignored notify same as -b nounset same as -u onecmd same as -t physical same as -P pipefail the return value of a pipeline is the status of the last command to exit with a non-zero status, or zero if no command exited with a non-zero status posix change the behavior of bash where the default operation differs from the Posix standard to match the standard privileged same as -p verbose same as -v vi use a vi-style line editing interface xtrace same as -x -p Turned on whenever the real and effective user ids do not match. Disables processing of the $ENV file and importing of shell functions. Turning this option off causes the effective uid and gid to be set to the real uid and gid. -t Exit after reading and executing one command. -u Treat unset variables as an error when substituting. -v Print shell input lines as they are read. -x Print commands and their arguments as they are executed. -B the shell will perform brace expansion -C If set, disallow existing regular files to be overwritten by redirection of output. -E If set, the ERR trap is inherited by shell functions. -H Enable ! style history substitution. This flag is on by default when the shell is interactive. -P If set, do not follow symbolic links when executing commands such as cd which change the current directory. -T If set, the DEBUG trap is inherited by shell functions. -- Assign any remaining arguments to the positional parameters. If there are no remaining arguments, the positional parameters are unset. - Assign any remaining arguments to the positional parameters. The -x and -v options are turned off. Using + rather than - causes these flags to be turned off. The flags can also be used upon invocation of the shell. The current set of flags may be found in $-. The remaining n ARGs are positional parameters and are assigned, in order, to $1, $2, .. $n. If no ARGs are given, all shell variables are printed. Exit Status: Returns success unless an invalid option is given.

Set export attribute for shell variables. Marks each NAME for automatic export to the environment of subsequently executed commands. If VALUE is supplied, assign VALUE before exporting. Options: -f refer to shell functions -n remove the export property from each NAME -p display a list of all exported variables and functions An argument of `--' disables further option processing. Exit Status: Returns success unless an invalid option is given or NAME is invalid.

Mark shell variables as unchangeable. Mark each NAME as read-only; the values of these NAMEs may not be changed by subsequent assignment. If VALUE is supplied, assign VALUE before marking as read-only. Options: -a refer to indexed array variables -A refer to associative array variables -f refer to shell functions -p display a list of all readonly variables and functions An argument of `--' disables further option processing. Exit Status: Returns success unless an invalid option is given or NAME is invalid.

Shift positional parameters. Rename the positional parameters $N+1,$N+2 ... to $1,$2 ... If N is not given, it is assumed to be 1. Exit Status: Returns success unless N is negative or greater than $#.

Evaluate conditional expression. Exits with a status of 0 (true) or 1 (false) depending on the evaluation of EXPR. Expressions may be unary or binary. Unary expressions are often used to examine the status of a file. There are string operators and numeric comparison operators as well. The behavior of test depends on the number of arguments. Read the bash manual page for the complete specification. File operators: -a FILE True if file exists. -b FILE True if file is block special. -c FILE True if file is character special. -d FILE True if file is a directory. -e FILE True if file exists. -f FILE True if file exists and is a regular file. -g FILE True if file is set-group-id. -h FILE True if file is a symbolic link. -L FILE True if file is a symbolic link. -k FILE True if file has its `sticky' bit set. -p FILE True if file is a named pipe. -r FILE True if file is readable by you. -s FILE True if file exists and is not empty. -S FILE True if file is a socket. -t FD True if FD is opened on a terminal. -u FILE True if the file is set-user-id. -w FILE True if the file is writable by you. -x FILE True if the file is executable by you. -O FILE True if the file is effectively owned by you. -G FILE True if the file is effectively owned by your group. -N FILE True if the file has been modified since it was last read. FILE1 -nt FILE2 True if file1 is newer than file2 (according to modification date). FILE1 -ot FILE2 True if file1 is older than file2. FILE1 -ef FILE2 True if file1 is a hard link to file2. String operators: -z STRING True if string is empty. -n STRING STRING True if string is not empty. STRING1 = STRING2 True if the strings are equal. STRING1 != STRING2 True if the strings are not equal. STRING1 < STRING2 True if STRING1 sorts before STRING2 lexicographically. STRING1 > STRING2 True if STRING1 sorts after STRING2 lexicographically. Other operators: -o OPTION True if the shell option OPTION is enabled. -v VAR True if the shell variable VAR is set ! EXPR True if expr is false. EXPR1 -a EXPR2 True if both expr1 AND expr2 are true. EXPR1 -o EXPR2 True if either expr1 OR expr2 is true. arg1 OP arg2 Arithmetic tests. OP is one of -eq, -ne, -lt, -le, -gt, or -ge. Arithmetic binary operators return true if ARG1 is equal, not-equal, less-than, less-than-or-equal, greater-than, or greater-than-or-equal than ARG2. Exit Status: Returns success if EXPR evaluates to true; fails if EXPR evaluates to false or an invalid argument is given.

Evaluate conditional expression. This is a synonym for the "test" builtin, but the last argument must be a literal `]', to match the opening `['.

Trap signals and other events. Defines and activates handlers to be run when the shell receives signals or other conditions. ARG is a command to be read and executed when the shell receives the signal(s) SIGNAL_SPEC. If ARG is absent (and a single SIGNAL_SPEC is supplied) or `-', each specified signal is reset to its original value. If ARG is the null string each SIGNAL_SPEC is ignored by the shell and by the commands it invokes. If a SIGNAL_SPEC is EXIT (0) ARG is executed on exit from the shell. If a SIGNAL_SPEC is DEBUG, ARG is executed before every simple command. If a SIGNAL_SPEC is RETURN, ARG is executed each time a shell function or a script run by the . or source builtins finishes executing. A SIGNAL_SPEC of ERR means to execute ARG each time a command's failure would cause the shell to exit when the -e option is enabled. If no arguments are supplied, trap prints the list of commands associated with each signal. Options: -l print a list of signal names and their corresponding numbers -p display the trap commands associated with each SIGNAL_SPEC Each SIGNAL_SPEC is either a signal name in <signal.h> or a signal number. Signal names are case insensitive and the SIG prefix is optional. A signal may be sent to the shell with "kill -signal $$". Exit Status: Returns success unless a SIGSPEC is invalid or an invalid option is given.

Display information about command type. For each NAME, indicate how it would be interpreted if used as a command name. Options: -a display all locations containing an executable named NAME; includes aliases, builtins, and functions, if and only if the `-p' option is not also used -f suppress shell function lookup -P force a PATH search for each NAME, even if it is an alias, builtin, or function, and returns the name of the disk file that would be executed -p returns either the name of the disk file that would be executed, or nothing if `type -t NAME' would not return `file'. -t output a single word which is one of `alias', `keyword', `function', `builtin', `file' or `', if NAME is an alias, shell reserved word, shell function, shell builtin, disk file, or not found, respectively Arguments: NAME Command name to be interpreted. Exit Status: Returns success if all of the NAMEs are found; fails if any are not found.

Display or set file mode mask. Sets the user file-creation mask to MODE. If MODE is omitted, prints the current value of the mask. If MODE begins with a digit, it is interpreted as an octal number; otherwise it is a symbolic mode string like that accepted by chmod(1). Options: -p if MODE is omitted, output in a form that may be reused as input -S makes the output symbolic; otherwise an octal number is output Exit Status: Returns success unless MODE is invalid or an invalid option is given.

Wait for job completion and return exit status. Waits for the process identified by ID, which may be a process ID or a job specification, and reports its termination status. If ID is not given, waits for all currently active child processes, and the return status is zero. If ID is a a job specification, waits for all processes in the job's pipeline. Exit Status: Returns the status of ID; fails if ID is invalid or an invalid option is given.

Execute commands for each member in a list. The `for' loop executes a sequence of commands for each member in a list of items. If `in WORDS ...;' is not present, then `in "$@"' is assumed. For each element in WORDS, NAME is set to that element, and the COMMANDS are executed. Exit Status: Returns the status of the last command executed.

Arithmetic for loop. Equivalent to (( EXP1 )) while (( EXP2 )); do COMMANDS (( EXP3 )) done EXP1, EXP2, and EXP3 are arithmetic expressions. If any expression is omitted, it behaves as if it evaluates to 1. Exit Status: Returns the status of the last command executed.

Select words from a list and execute commands. The WORDS are expanded, generating a list of words. The set of expanded words is printed on the standard error, each preceded by a number. If `in WORDS' is not present, `in "$@"' is assumed. The PS3 prompt is then displayed and a line read from the standard input. If the line consists of the number corresponding to one of the displayed words, then NAME is set to that word. If the line is empty, WORDS and the prompt are redisplayed. If EOF is read, the command completes. Any other value read causes NAME to be set to null. The line read is saved in the variable REPLY. COMMANDS are executed after each selection until a break command is executed. Exit Status: Returns the status of the last command executed.

Execute commands based on conditional. The `if COMMANDS' list is executed. If its exit status is zero, then the `then COMMANDS' list is executed. Otherwise, each `elif COMMANDS' list is executed in turn, and if its exit status is zero, the corresponding `then COMMANDS' list is executed and the if command completes. Otherwise, the `else COMMANDS' list is executed, if present. The exit status of the entire construct is the exit status of the last command executed, or zero if no condition tested true. Exit Status: Returns the status of the last command executed.

Create a coprocess named NAME. Execute COMMAND asynchronously, with the standard output and standard input of the command connected via a pipe to file descriptors assigned to indices 0 and 1 of an array variable NAME in the executing shell. The default NAME is "COPROC". Exit Status: Returns the exit status of COMMAND.

Common shell variable names and usage. BASH_VERSION Version information for this Bash. CDPATH A colon-separated list of directories to search for directories given as arguments to `cd'. GLOBIGNORE A colon-separated list of patterns describing filenames to be ignored by pathname expansion. HISTFILE The name of the file where your command history is stored. HISTFILESIZE The maximum number of lines this file can contain. HISTSIZE The maximum number of history lines that a running shell can access. HOME The complete pathname to your login directory. HOSTNAME The name of the current host. HOSTTYPE The type of CPU this version of Bash is running under. IGNOREEOF Controls the action of the shell on receipt of an EOF character as the sole input. If set, then the value of it is the number of EOF characters that can be seen in a row on an empty line before the shell will exit (default 10). When unset, EOF signifies the end of input. MACHTYPE A string describing the current system Bash is running on. MAILCHECK How often, in seconds, Bash checks for new mail. MAILPATH A colon-separated list of filenames which Bash checks for new mail. OSTYPE The version of Unix this version of Bash is running on. PATH A colon-separated list of directories to search when looking for commands. PROMPT_COMMAND A command to be executed before the printing of each primary prompt. PS1 The primary prompt string. PS2 The secondary prompt string. PWD The full pathname of the current directory. SHELLOPTS A colon-separated list of enabled shell options. TERM The name of the current terminal type. TIMEFORMAT The output format for timing statistics displayed by the `time' reserved word. auto_resume Non-null means a command word appearing on a line by itself is first looked for in the list of currently stopped jobs. If found there, that job is foregrounded. A value of `exact' means that the command word must exactly match a command in the list of stopped jobs. A value of `substring' means that the command word must match a substring of the job. Any other value means that the command must be a prefix of a stopped job. histchars Characters controlling history expansion and quick substitution. The first character is the history substitution character, usually `!'. The second is the `quick substitution' character, usually `^'. The third is the `history comment' character, usually `#'. HISTIGNORE A colon-separated list of patterns used to decide which commands should be saved on the history list.

Add directories to stack. Adds a directory to the top of the directory stack, or rotates the stack, making the new top of the stack the current working directory. With no arguments, exchanges the top two directories. Options: -n Suppresses the normal change of directory when adding directories to the stack, so only the stack is manipulated. Arguments: +N Rotates the stack so that the Nth directory (counting from the left of the list shown by `dirs', starting with zero) is at the top. -N Rotates the stack so that the Nth directory (counting from the right of the list shown by `dirs', starting with zero) is at the top. dir Adds DIR to the directory stack at the top, making it the new current working directory. The `dirs' builtin displays the directory stack. Exit Status: Returns success unless an invalid argument is supplied or the directory change fails.

Remove directories from stack. Removes entries from the directory stack. With no arguments, removes the top directory from the stack, and changes to the new top directory. Options: -n Suppresses the normal change of directory when removing directories from the stack, so only the stack is manipulated. Arguments: +N Removes the Nth entry counting from the left of the list shown by `dirs', starting with zero. For example: `popd +0' removes the first directory, `popd +1' the second. -N Removes the Nth entry counting from the right of the list shown by `dirs', starting with zero. For example: `popd -0' removes the last directory, `popd -1' the next to last. The `dirs' builtin displays the directory stack. Exit Status: Returns success unless an invalid argument is supplied or the directory change fails.

Set and unset shell options. Change the setting of each shell option OPTNAME. Without any option arguments, list all shell options with an indication of whether or not each is set. Options: -o restrict OPTNAMEs to those defined for use with `set -o' -p print each shell option with an indication of its status -q suppress output -s enable (set) each OPTNAME -u disable (unset) each OPTNAME Exit Status: Returns success if OPTNAME is enabled; fails if an invalid option is given or OPTNAME is disabled.

Specify how arguments are to be completed by Readline. For each NAME, specify how arguments are to be completed. If no options are supplied, existing completion specifications are printed in a way that allows them to be reused as input. Options: -p print existing completion specifications in a reusable format -r remove a completion specification for each NAME, or, if no NAMEs are supplied, all completion specifications -D apply the completions and actions as the default for commands without any specific completion defined -E apply the completions and actions to "empty" commands -- completion attempted on a blank line When completion is attempted, the actions are applied in the order the uppercase-letter options are listed above. The -D option takes precedence over -E. Exit Status: Returns success unless an invalid option is supplied or an error occurs.

Modify or display completion options. Modify the completion options for each NAME, or, if no NAMEs are supplied, the completion currently being executed. If no OPTIONs are given, print the completion options for each NAME or the current completion specification. Options: -o option Set completion option OPTION for each NAME -D Change options for the "default" command completion -E Change options for the "empty" command completion Using `+o' instead of `-o' turns off the specified option. Arguments: Each NAME refers to a command for which a completion specification must have previously been defined using the `complete' builtin. If no NAMEs are supplied, compopt must be called by a function currently generating completions, and the options for that currently-executing completion generator are modified. Exit Status: Returns success unless an invalid option is supplied or NAME does not have a completion specification defined.

Read lines from the standard input into an indexed array variable. Read lines from the standard input into the indexed array variable ARRAY, or from file descriptor FD if the -u option is supplied. The variable MAPFILE is the default ARRAY. Options: -n count Copy at most COUNT lines. If COUNT is 0, all lines are copied. -O origin Begin assigning to ARRAY at index ORIGIN. The default index is 0. -s count Discard the first COUNT lines read. -t Remove a trailing newline from each line read. -u fd Read lines from file descriptor FD instead of the standard input. -C callback Evaluate CALLBACK each time QUANTUM lines are read. -c quantum Specify the number of lines read between each call to CALLBACK. Arguments: ARRAY Array variable name to use for file data. If -C is supplied without -c, the default quantum is 5000. When CALLBACK is evaluated, it is supplied the index of the next array element to be assigned and the line to be assigned to that element as additional arguments. If not supplied with an explicit origin, mapfile will clear ARRAY before assigning to it. Exit Status: Returns success unless an invalid option is given or ARRAY is readonly or not an indexed array.