Browsing Chinese (Traditional) translation

492.

Print the name of the current working directory.

Options:
-L[tab]print the value of $PWD if it names the current working
[tab]directory
-P[tab]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.

496.

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[tab]use a default value for PATH that is guaranteed to find all of
[tab]the standard utilities
-v[tab]print a description of COMMAND similar to the `type' builtin
-V[tab]print a more verbose description of each COMMAND

Exit Status:
Returns exit status of COMMAND, or failure if COMMAND is not found.

497.

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[tab]restrict action or display to function names and definitions
-F[tab]restrict display to function names only (plus line number and
[tab]source file when debugging)
-g[tab]create global variables when used in a shell function; otherwise
[tab]ignored
-p[tab]display the attributes and value of each NAME

Options which set attributes:
-a[tab]to make NAMEs indexed arrays (if supported)
-A[tab]to make NAMEs associative arrays (if supported)
-i[tab]to make NAMEs have the `integer' attribute
-l[tab]to convert NAMEs to lower case on assignment
-n[tab]make NAME a reference to the variable named by its value
-r[tab]to make NAMEs readonly
-t[tab]to make NAMEs have the `trace' attribute
-u[tab]to convert NAMEs to upper case on assignment
-x[tab]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 a variable
assignment error occurs.

498.

Set variable values and attributes.

Obsolete. See `help declare'.

500.

Write arguments to the standard output.

Display the ARGs, separated by a single space character and followed by a
newline, on the standard output.

Options:
-n[tab]do not append a newline
-e[tab]enable interpretation of the following backslash escapes
-E[tab]explicitly suppress interpretation of backslash escapes

`echo' interprets the following backslash-escaped characters:
\a[tab]alert (bell)
\b[tab]backspace
\c[tab]suppress further output
\e[tab]escape character
\E[tab]escape character
\f[tab]form feed
\n[tab]new line
\r[tab]carriage return
\t[tab]horizontal tab
\v[tab]vertical tab
\\[tab]backslash
\0nnn[tab]the character whose ASCII code is NNN (octal). NNN can be
[tab]0 to 3 octal digits
\xHH[tab]the eight-bit character whose value is HH (hexadecimal). HH
[tab]can be one or two hex digits

Exit Status:
Returns success unless a write error occurs.

505.

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[tab]pass NAME as the zeroth argument to COMMAND
-c[tab][tab]execute COMMAND with an empty environment
-l[tab][tab]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.

511.

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[tab][tab]forget the remembered location of each NAME
-l[tab][tab]display in a format that may be reused as input
-p pathname[tab]use PATHNAME as the full pathname of NAME
-r[tab][tab]forget all remembered locations
-t[tab][tab]print the remembered location of each NAME, preceding
[tab][tab]each location with the corresponding NAME if multiple
[tab][tab]NAMEs are given
Arguments:
NAME[tab][tab]Each NAME is searched for in $PATH and added to the list
[tab][tab]of remembered commands.

Exit Status:
Returns success unless NAME is not found or an invalid option is given.

512.

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[tab]output short description for each topic
-m[tab]display usage in pseudo-manpage format
-s[tab]output only a short usage synopsis for each topic matching
[tab]PATTERN

Arguments:
PATTERN[tab]Pattern specifiying a help topic

Exit Status:
Returns success unless PATTERN is not found or an invalid option is given.

513.

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[tab]clear the history list by deleting all of the entries
-d offset[tab]delete the history entry at offset OFFSET.

-a[tab]append history lines from this session to the history file
-n[tab]read all history lines not already read from the history file
-r[tab]read the history file and append the contents to the history
[tab]list
-w[tab]write the current history to the history file
[tab]and append them to the history list

-p[tab]perform history expansion on each ARG and display the result
[tab]without storing it in the history list
-s[tab]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.

514.

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[tab]lists process IDs in addition to the normal information
-n[tab]lists only processes that have changed status since the last
[tab]notification
-p[tab]lists process IDs only
-r[tab]restrict output to running jobs
-s[tab]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.