Translations by Mingye Wang

bind [-lpsvPSVX] [-m keymap] [-f filename] [-q name] [-u name] [-r keyseq] [-x keyseq:shell-command] [keyseq:readline-function or readline-command]

cd [-L|[-P [-e]] [-@]] [dir]

declare [-aAfFgilnrtux] [-p] [name[=value] ...]

typeset [-aAfFgilnrtux] [-p] name[=value] ...

unset [-f] [-v] [-n] [name ...]

ulimit [-SHabcdefiklmnpqrstuvxPT] [limit]

wait [pid ...]

compgen [-abcdefgjksuv] [-o option] [-A action] [-G globpat] [-W wordlist] [-F function] [-C command] [-X filterpat] [-P prefix] [-S suffix] [word]

mapfile [-d delim] [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callback] [-c quantum] [array]

Define or display aliases. Without arguments, `alias' prints the list of aliases in the reusable form `alias NAME=VALUE' on standard output. Otherwise, an alias is defined for each NAME whose VALUE is given. A trailing space in VALUE causes the next word to be checked for alias substitution when the alias is expanded. Options: -p print all defined aliases in a reusable format Exit Status: alias returns true unless a NAME is supplied for which no alias has been defined.

Remove each NAME from the list of defined aliases. Options: -a remove all alias definitions Return success unless a NAME is not an existing alias.

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. -X List key sequences bound with -x and associated commands in a form that can be reused as input. 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: resolve symbolic links in DIR after processing instances of `..' -P use the physical directory structure without following symbolic links: resolve symbolic links in DIR before processing instances of `..' -e if the -P option is supplied, and the current working directory cannot be determined successfully, exit with a non-zero status -@ on systems that support it, present a file with extended attributes as a directory containing the file attributes The default is to follow symbolic links, as if `-L' were specified. `..' is processed by removing the immediately previous pathname component back to a slash or the beginning of DIR. 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.

Execute a simple command or display information about commands. Runs COMMAND with ARGS suppressing shell function lookup, or display information about the specified COMMANDs. Can be used to invoke commands on disk when a function with the same name exists. Options: -p use a default value for PATH that is guaranteed to find all of the standard utilities -v print a description of COMMAND similar to the `type' builtin -V print a more verbose description of each COMMAND Exit Status: Returns exit status of COMMAND, or failure if COMMAND is not found.

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, a variable assignment error occurs, or the shell is not executing a function.

Replace the shell with the given command. Execute COMMAND, replacing this shell with the specified program. ARGUMENTS become the arguments to COMMAND. If COMMAND is not specified, any redirections take effect in the current shell. Options: -a name pass NAME as the zeroth argument to COMMAND -c execute COMMAND with an empty environment -l place a dash in the zeroth argument to COMMAND If the command cannot be executed, a non-interactive shell exits, unless the shell option `execfail' is set. Exit Status: Returns success unless COMMAND is not found or a redirection error occurs.

Remember or display program locations. Determine and remember the full pathname of each command NAME. If no arguments are given, information about remembered commands is displayed. Options: -d forget the remembered location of each NAME -l display in a format that may be reused as input -p pathname use PATHNAME as the full pathname of NAME -r forget all remembered locations -t print the remembered location of each NAME, preceding each location with the corresponding NAME if multiple NAMEs are given Arguments: NAME Each NAME is searched for in $PATH and added to the list of remembered commands. Exit Status: Returns success unless NAME is not found or an invalid option is given.

Display status of jobs. Lists the active jobs. JOBSPEC restricts output to that job. Without options, the status of all active jobs is displayed. Options: -l lists process IDs in addition to the normal information -n lists only processes that have changed status since the last notification -p lists process IDs only -r restrict output to running jobs -s restrict output to stopped jobs If -x is supplied, COMMAND is run after all job specifications that appear in ARGS have been replaced with the process ID of that job's process group leader. Exit Status: Returns success unless an invalid option is given or an error occurs. If -x is used, returns the exit status of COMMAND.

Remove jobs from current shell. Removes each JOBSPEC argument from the table of active jobs. Without any JOBSPECs, the shell uses its notion of the current job. Options: -a remove all jobs if JOBSPEC is not supplied -h mark each JOBSPEC so that SIGHUP is not sent to the job if the shell receives a SIGHUP -r remove only running jobs Exit Status: Returns success unless an invalid option or JOBSPEC is given.

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.

Unset values and attributes of shell variables and functions. For each NAME, remove the corresponding variable or function. Options: -f treat each NAME as a shell function -v treat each NAME as a shell variable -n treat each NAME as a name reference and unset the variable itself rather than the variable it references Without options, unset first tries to unset a variable, and if that fails, tries to unset a function. Some variables cannot be unset; also see `readonly'. Exit Status: Returns success unless an invalid option is given or a NAME is read-only.

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 or functions, depending on whether or not the -f option is given An argument of `--' disables further option processing. Exit Status: Returns success unless an invalid option is given or NAME is invalid.

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. -R VAR True if the shell variable VAR is set and is a name reference. ! 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.

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.

Modify shell resource limits. Provides control over the resources available to the shell and processes it creates, on systems that allow such control. Options: -S use the `soft' resource limit -H use the `hard' resource limit -a all current limits are reported -b the socket buffer size -c the maximum size of core files created -d the maximum size of a process's data segment -e the maximum scheduling priority (`nice') -f the maximum size of files written by the shell and its children -i the maximum number of pending signals -k the maximum number of kqueues allocated for this process -l the maximum size a process may lock into memory -m the maximum resident set size -n the maximum number of open file descriptors -p the pipe buffer size -q the maximum number of bytes in POSIX message queues -r the maximum real-time scheduling priority -s the maximum stack size -t the maximum amount of cpu time in seconds -u the maximum number of user processes -v the size of virtual memory -x the maximum number of file locks -P the maximum number of pseudoterminals -T the maximum number of threads Not all options are available on all platforms. If LIMIT is given, it is the new value of the specified resource; the special LIMIT values `soft', `hard', and `unlimited' stand for the current soft limit, the current hard limit, and no limit, respectively. Otherwise, the current value of the specified resource is printed. If no option is given, then -f is assumed. Values are in 1024-byte increments, except for -t, which is in seconds, -p, which is in increments of 512 bytes, and -u, which is an unscaled number of processes. Exit Status: Returns success unless an invalid option is supplied or an error occurs.

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 process completion and return exit status. Waits for each process specified by a PID and reports its termination status. If PID is not given, waits for all currently active child processes, and the return status is zero. PID must be a process ID. Exit Status: Returns the status of the last PID; fails if PID is invalid or an invalid option is given.

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.

Display directory stack. Display the list of currently remembered directories. Directories find their way onto the list with the `pushd' command; you can get back up through the list with the `popd' command. Options: -c clear the directory stack by deleting all of the elements -l do not print tilde-prefixed versions of directories relative to your home directory -p print the directory stack with one entry per line -v print the directory stack with one entry per line prefixed with its position in the stack Arguments: +N Displays the Nth entry counting from the left of the list shown by dirs when invoked without options, starting with zero. -N Displays the Nth entry counting from the right of the list shown by dirs when invoked without options, starting with zero. Exit Status: Returns success unless an invalid option is supplied or an error occurs.

Formats and prints ARGUMENTS under control of the FORMAT. Options: -v var assign the output to shell variable VAR rather than display it on the standard output FORMAT is a character string which contains three types of objects: plain characters, which are simply copied to standard output; character escape sequences, which are converted and copied to the standard output; and format specifications, each of which causes printing of the next successive argument. In addition to the standard format specifications described in printf(1), printf interprets: %b expand backslash escape sequences in the corresponding argument %q quote the argument in a way that can be reused as shell input %(fmt)T output the date-time string resulting from using FMT as a format string for strftime(3) The format is re-used as necessary to consume all of the arguments. If there are fewer arguments than the format requires, extra format specifications behave as if a zero value or null string, as appropriate, had been supplied. Exit Status: Returns success unless an invalid option is given or a write or assignment error occurs.

Display possible completions depending on the options. Intended to be used from within a shell function generating possible completions. If the optional WORD argument is supplied, matches against WORD are generated. Exit Status: Returns success unless an invalid option is supplied or an error occurs.

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: -d delim Use DELIM to terminate lines, instead of newline -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 DELIM from each line read (default newline) -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.