"Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid." – Albert Einstein

Linux cmd start with “a”



1. accept

accept [option] destination

System administration command. Instruct printing system to accept jobs for the specified print queue or queues. Depending on queue settings, the system may prompt for a password. Also invoked as cupsaccept.

Option

-E

Require encryption when connecting.


2. access

access [mode] [filename]

Check whether a file is available for the action specified with the mode argument: r for read, w for write, x for execute. Used mostly in scripting, access works better than test because it uses a direct system call rather than looking at the file permissions, which can be misleading when a filesystem is mounted read-only.

Options

–help

Display help message, then quit.

–version

Display version, then quit.

.


3. aclocal


aclocal [options]

GNU autoconf tool. Place m4 macro definitions needed by autoconf into a single file. The aclocal command first scans for macro definitions in m4 files in its default directory (/usr/share/aclocal on some systems) and in the file acinclude.m4. It next scans for macros used in the configure.in file. It generates an aclocal.m4 file that contains definitions of all m4 macros required by autoconf.

Options

–acdir=dir

Look for macro files in directory dir instead of the default directory.

–help

Print help message, then exit.

-I dir

Additionally, search directory dir for m4 macro definitions.

–output=file

Save output to file instead of aclocal.m4.

–print-ac-dir

Print the name of the directory to be searched for m4 files, then exit.

–verbose

Print names of files being processed.

–version

Print version number, then exit.


4. aconnect


aconnect [options] [sender] [receiver]
aconnect [options]

Like its GUI relative alsa-patch-bay, aconnect connects ports in MIDI hardware and software to route events, similar to running patch cables between different mixers and synthesizers in an all-hardware audio system. aconnect is part of the ALSA (Advanced Linux Sound Architecture) system.

Options

-d,–disconnect

Undo the connection described.

-e,–exclusive

The connection being created must be exclusive: the sender and receiver ports may not connect to any other port.

-i,–input

List all input (sender) ports. This flag is used without any other arguments or flags.

-o, –output

List all output (receiver) ports. This flag is used without any other arguments or flags.

-r, –real queue-name

All events processed through this connection get new timestamps from the named real-time queue. The receiving port must have access to, and use, the real-time queue.

-t, –tick queue-name

All events processed through this connection get new timestamps from the specified tick queue.

-x, –remove-all

Cancel all connections. This flag is used without any other arguments or flags.


5. acpi


acpi [options]Displays information about the ACPI (Advanced Configuration and Power Interface) system, based on the /proc/acpi file. Most kernels after 2.4 support ACPI hardware, and in both hardware and software, ACPI is gradually replacing the older APM (Advanced Power Management) system. Some operating systems, including SUSE, ship a combined ACPI/APM power interface called powersaved. Most, however, require either ACPI or APM software.

Note that some ACPI systems have special events that are not available on others. For example, IBM laptops have events related to their docking stations and keyboard lights that are not used on nondocking or unlighted laptops. On all systems, the /proc/acpi directory must be present for acpi commands to work.

Options

-b, –battery

Display battery information.

-B, –without-battery

Do not display battery information.

-t, –thermal

Display temperature information.

-T, –without-thermal

Do not display temperature information.

-a, –ac-adapter

Show whether the AC adapter is connected.

-A, –without-ac-adapter

Do not show information about the AC adapter.

-V, –everything

Show all information on every device.

-s, –show-empty

Display information even on devices that are not available or not installed, such as empty slots for extra batteries.

-S, –hide-empty

Do not display information on devices that are not operational or not installed.

-c, –celcius

Use degrees Celsius as the temperature unit. This is the default unit.

-d, –directory /path

Use the specified path to ACPI information. The default path is /proc/acpi.

-f, –fahrenheit

Use degrees Fahrenheit as the temperature unit.

-h, –help

Display help information.

-k, –kelvin

Use degrees Kelvin as the temperature unit.

-v, –version

Display version information.


6. acpi_available


acpi_available

Determine whether ACPI functionality exists. Returns 0 for true and 1 for false.


7. acpid


acpid [options]Daemon that informs user-space programs about ACPI (Advanced Configuration and Power Interface) events, such as battery warnings, power-supply changes, and laptop lid closings. As ACPI hardware replaces older APM (Advanced Power Management) hardware, acpid replaces apmd. Like other daemons, this application is controlled primarily through a configuration file that determines which events merit action, and what those actions are. In some operating systems, including SUSE Linux and its relatives, all power management is handled by a combined ACPI/APM system called powersave and this daemon is not installed.

Options

-c directory, –confdir=directory

Set the directory used for configuration files. The default directory is /etc/acpi/events. All files in this directory, except those beginning with a period (.), are parsed as configuration files. Typically, a single file is used for each ACPI event to be acted upon.

In the configuration files, blank lines and those beginning with # are ignored. Other lines are expected to consist of a regular expression and a command to be executed when an ACPI event matches the expression.

-d, –debug

Debug mode: run the daemon in the foreground and send all log output to stderr and stdout, rather than a logfile.

-e filename,–eventfile=filename

Set the file used to find events. Normally this is /proc/acpi/event.

-g group,–socketgroup=group

Set the group ownership of the socket to which acpid publishes events. This allows you to restrict which users on the system can access ACPI event information.

-l filename,–logfile=filename

Set the logfile location. Normally, it is /var/log/acpid.

-m mode,–socketmode=mode

Set the permission mode of the socket. Normally, it is 666, with the sticky bit off.

-s filename,–socketfile=filename

Set the file used to define the socket. Normally, this is /var/run/acpid.socket.

-S,–nosocket

Tells acpid not to open a socket at all. Overrides all other socket options.

-v,–version

Print version information and quit.

-h,–help

Print help message and quit.


8. addr2line


addr2line [options] [addresses]

Translate hexadecimal program addresses into filenames and line numbers for the executable given with the -e option, or a.out if -e is not specified. If addresses are given on the command line, display the filename and line number for each address. Otherwise, read the addresses from standard input and display the results on standard output (useful for use in a pipe). addr2line prints two question marks (??) if it cannot determine a filename, and 0 if it cannot determine the line number. addr2line is used for debugging.

Options

-b bfdname, –target=bfdname

Set the binary file format using its binary file descriptor name, bfdname. Use the -h option for a list of supported formats for your system.

-C, –demangle[=style]

Decode (demangle) low-level symbol names into usernames. See the -h help output for a list of styles supported by your compiler.

-e file, –exe=file

Specify the filename of the executable to use. The default filename is a.out.

-f, –functions

Display function names in addition to filenames and line numbers.

-h, –help

Display help information and exit.

-s, –basenames

Strip directories off filenames and show only the basenames.


9. addresses


addresses [-p port]

Connect to the PalmOS device on the specified port, and dump the addresses from the address book to stdout. Part of the pilot-link package of tools for managing PalmOS devices.


10. agetty


agetty [options] port baudrate [term]

System administration command. The Linux version of getty. Set terminal type, modes, speed, and line discipline. agetty is invoked by init. It is the second process in the series init-getty-login-shell, which ultimately connects a user with the Linux system. agetty reads the user’s login name and invokes the login command with the user’s name as an argument. While reading the name, agetty attempts to adapt the system to the speed and type of device being used.

You must specify a port, which agetty will search for in the /dev directory. You may use , in which case agetty reads from standard input. You must also specify baudrate, which may be a comma-separated list of rates through which agetty will step. Optionally, you may specify the term, which is used to override the TERM environment variable.

Options

-f file

Specify the use of file instead of /etc/issue upon connection to terminal. It is overridden by -i.

-h

Specify hardware, not software, flow control.

-H hostname

Write login hostname into the utmp file. By default, no login host is specified.

-I string

Specify string to be sent to the tty or modem.

-i

Suppress printing of /etc/issue before printing the login prompt.

-l program

Specify the use of program instead of /bin/login.

-L

Do not require carrier detect; operate locally only. Use this when connecting terminals.

-m

Attempt to guess the appropriate baud rate.

-n

Don’t prompt for a login name.

-t timeout

Specify that agetty should exit if the open on the line succeeds and there is no response to the login prompt in timeout seconds.

-w

Wait for carriage return or linefeed before sending login prompt. Use when sending an initialization string.


11. alsactl


alsactl [options] [store|restore] card

Controls advanced configuration settings for sound cards using the ALSA (Advanced Linux Sound Architecture) system. Settings are written to configuration files using the store function and loaded from those files with the restore function.

Options

-d,–debug

Debug mode: increased information output to the console.

-f file, –f=file

Specify the use of file instead of /etc/asound.state as a configuration file.

-F,–force

Force the restoration of settings.

-h,–help

Display help message and quit.

-v,–version

Display version information and quit.


12. amidi


amidi [options]

Read and write raw MIDI files (.syx format, without timing information) to ALSA ports. For standard MIDI (.mid) files, use aplaymidi and arecordmidi.

Options

-a,–active-sensing

Record and send active-sensing (FEh) bytes in MIDI commands. By default, these bytes are ignored.

-d,–dump

Output all received data directly to the screen.

-h,–help

Display help information and quit.

-l,–list-devices

List all hardware MIDI ports.

-L,–list-rawmidis

List all RawMIDI definitions. Useful for debugging configuration files.

-p,–port=name

Use the specified port. This overrides the port set in the configuration file. If neither this flag nor the configuration file sets a port, the default is port 0 on device 0, which may or may not exist.

-r,–receive=filename

Write data from the port specified with the -p or –port flag to the file named here. This will be a raw file, and should end in .syx. Unless you use the -a option, it will not contain any Active Sensing (FEh) bytes.

-s,–send=filename

Send the file to the port specified with the -p or –port flag. Use raw (.syx) MIDI files only.

-S,–send-hex=”hex-numbers…

Send a string of hexadecimal numbers to the port specified with the -p or –port flag.

-t,–timeout=n

Stop listening after n seconds of receiving no data.

-V,–version

Display version information and quit.


13. amixer


amixer [-ccard] [command]

Command-line ALSA mixer. For an ncurses interface, use alsamixer. amixer displays or changes the current mixer settings for the current sound card and sound device. To display all mixer settings, use with no flags or commands.

Commands

controls

Displays a complete list of card controls. These controls can be set with the cset command, in contrast to simple mixer controls, which use set or sset.

contents

List card controls and their contents.

cget [control]

Display the contents of the specified card control.

cset [control] [parameter]

Set the card control to the value specified in the parameter. Card controls may be identified by iface, name, index, device, subdevice, or numid. The parameter will normally be a number or percentage value. For example, the command amixer -c 1 cset numid=16 50% will set the 16th element of the first sound card to 50%.

get,sget [control]

Display the current values for the specified control.

help

Display help message and quit.

info

Displays information about the card specified with the -c flag.

scontrols

Display a list of simple mixer controls. Simple mixer controls can be set with the set or sset commands, in contrast to card controls, which use the cset command.

set,sset [control] [parameter]

Set one of the controls listed by scontrols. You can specify the volume with a percentage from 0% to 100%, or a specific hardware value. By appending + or – to the number, you will increase or decrease the volume by that amount. To set recording and muting values, use the parameters cap (meaning capture, or record), nocap,mute,unmute, or toggle. To specify individual channels, use the parameters front, rear, center, or woofer. For example, the command amixer -c 1 sset Line,0 100% unmute will set Line 0 on the first sound card to 100% and unmute it.

Options

-c n

The number of the card to adjust.

-D devicename

Specify the name of the device. By default, the name is default.

-h

Display help information and quit.

-q

Quiet mode: do not show the results of changes made.


14. anacron


anacron [options] [job]

System administration command. Normally started in a system startup file. Execute commands periodically. By default, anacron reads a list of jobs from a configuration file, /etc/anacrontab. The file consists of shell variables to use when running commands, followed by a list of tasks to run. Each task specifies how often in days it should be run, a delay in minutes to wait before running the task, a unique job identifier used to store a timestamp, and the shell command to execute. Timestamps for the last run of each task are stored in the /var/spool/anacron file. For each task, anacron compares the stored timestamp against the current time. If the command has not been executed within the specified frequency, the command is run. Upon completion, anacron records the new date in the timestamp file. Limit anacron to a specified task by providing the task’s unique job identifier on the command line.

The anacron command is often used to support the cron daemon on systems that do not run continuously.

Options

-d

Run in foreground rather than as a background process. Send messages to standard error.

-f

Run tasks ignoring timestamps.

-h

Print help message, then exit.

-n

Run tasks now, ignoring delay specifications.

-q

Suppress messages to standard error when using the -d option.

-s

Execute tasks serially. Do not start new task until previous task is completed.

-t file

Read tasks from file instead of from /etc/anacrontab.

-u

Update timestamps for tasks, but don’t run them.

-V

Print version number, then exit.


15. aplay


aplay [options] [file]

Play sound files using the ALSA sound system. The related arecord records sound files.

Options

-h

Print help message, then exit.

–version

Print version and quit.

-l,–list-devices

List available sound cards and digital audio devices.

-L,–list-pcms

List all PCM (pulse-coded modulation, or digital audio) devices that have been defined. PCMs may be defined in the .asoundrc file.

-D,–device=devicename

Select a PCM device by name.

-q

Do not display messages.

-t,–file-type=type

Name the file type used. Files may be voc, wav, raw, or au.

-c,–channels=n

Use n channels: 1 for mono, 2 for stereo.

-f,–format=format

Specify the sample format. The sample formats available will depend on hardware. For CD and DAT output, use the cd and dat shortcuts, which set the sample rate, format, and channel numbers all at once.

-r,–rate=n

Set the sample rate in Hertz.

-d,–duration=n

Set an interrupt for n seconds after playback begins.

-s,–sleep-min=n


16. aplaymidi


aplaymidi [options] [file]

Play MIDI files using the ALSA sound system; output is to ALSA sequencer ports.

Options

-d,–delay=n

Delay n seconds at the end of a file to allow for reverberation of the final notes.

-h

Print help message, then exit.

-V

Print version and quit.

-l

List output ports available.

-p,–port=client:port

Specify the port to which the MIDI file will be sent. If no port is specified, the file will be sent to port 0.


17. apm


apm [options]

Display current Advanced Power Management hardware information, such as battery life, or send the system into standby or suspend-to-disk mode. Used on older systems, and replaced by acpi and related commands.

-V, –version

Display version information and quit.

-v,–verbose

Verbose mode. Display information about the APM BIOS and Linux APM driver.

-m, –minutes

Display estimated minutes of battery life remaining. Default format is in hours and minutes.

-s, –suspend

Suspend system to disk. Suspending the system to disk is equivalent to turning it off, but boot time will be faster and the system will resume exactly where it was before suspend.

-S, –standby

Set system to standby. This will normally turn off the monitor and spin down the disk drives, reducing energy consumption by approximately 50 percent. Recovery from this mode is more rapid than from a full suspend to disk, but the system is still running.

-i,–ignore

When the system is using AC power, ignore suspend or standby requests generated by the system.

-n,–noignore

Do not ignore any suspend or standby events. This overrides a previously issued -i flag.


18. apmd


apmd [options]

System administration command. apmd handles events reported by the Advanced Power Management BIOS driver. The driver reports on battery level and requests to enter sleep or suspend mode. apmd will log any reports it gets via syslogd and take steps to make sure that basic sleep and suspend requests are handled gracefully. You can fine-tune the behavior of apmd by editing the apmd_proxy script, which apmd runs when it receives an event. Note that the APM hardware standard is gradually being replaced by the ACPI (Advanced Configuration and Power Interface) standard, and apmd by acpid. On SUSE Linux, both APM and ACPI hardware are handled by powersave and powersaved.

Options

-c n, –check n

Set the number of seconds to wait for an event before rechecking the power level. Default is to wait indefinitely. Setting this causes the battery levels to be checked more frequently.

-p n, –percentage n

Log information whenever the power changes by n percent. The default is 5. Values greater than 100 will disable logging of power changes.

-P command, –apmd_proxy command

Specify the apmd_proxy command to run when APM driver events are reported. This is generally a shell script. The command will be invoked with parameters indicating what kind of event was received. The parameters are listed in the next section.

-v, –verbose

Verbose mode; all events are logged.

-V, –version

Print version and exit.

-w n, –warn n

Log a warning at ALERT level when the battery charge drops below n percent. The default is 10. Negative values disable low-battery-level warnings.

-W, –wall

Use wall to alert all users of a low battery status.

-q, –quiet

Disable low-battery-level warnings.

-?, –help

Print help summary and exit.

Parameters

The apmd proxy script is invoked with the following parameters:

start

Invoked when the daemon starts.

stop

Invoked when the daemon stops.

suspend [ system | user ]

Invoked when the daemon receives a suspend request. The second parameter indicates whether the request was made by the system or by the user. Suspend, also known as “hibernate,” effectively powers the system down but has a quicker recovery than a normal boot process.

standby [ system | user ]

Invoked when the daemon receives a standby request. The second parameter indicates whether the request was made by the system or by the user. Standby mode powers off the monitor and disks, but the system continues to run and use power.

resume [ suspend | standby | critical ]

Invoked when the system resumes normal operation. The second parameter indicates the mode the system was in before resuming. critical suspends indicate an emergency shutdown. After a critical suspend, the system may be unstable, and you can use the resume command to help you recover from the suspension.

change power

Invoked when system power is changed from AC to battery or from battery to AC.

change battery

Invoked when the APM BIOS driver reports that the battery is low.

change capability

Invoked when the APM BIOS driver reports that some hardware that affects its capability has been added or removed.


19. apropos


apropos string …

Search the short manual page descriptions in the whatis database for occurrences of each string and display the result on the standard output. Like whatis, except that it searches for strings instead of words. Equivalent to man -k.


20. apt


apt

The Advanced Package Tool, the Debian package management system. A freely available packaging system for software distribution and installation. For detailed information on apt and its commands, see Chapter 5.


21. ar


ar key [args] [posname] [count] archive [files]

Maintain a group of files that are combined into a file archive. Used most commonly to create and update static library files, as used by the link editor (ld). Compiler frontends often call ar automatically. Only one key letter may be used, but each can be combined with additional args (with no separations between). posname is the name of a file in archive. When moving or replacing files, you can specify that they be placed before or after posname. ar has largely been superseded by tar and bzip2.

Keys

d

Delete files from archive.

m

Move files to end of archive.

p

Print files in archive.

q

Append files to archive.

r

Replace files in archive.

t

List the contents of archive or list the named files.

x

Extract contents from archive or only the named files.

Arguments

a

Use with r or m key to place files in the archive after posname.

b

Same as a, but before posname.

c

Create archive silently.

f

Truncate long filenames.

i

Same as b.

l

For backward compatibility; meaningless in Linux.

N

Use count parameter. Where multiple entries with the same name are found, use the count instance.

o

Preserve original timestamps.

P

Use full pathname. Useful for non-POSIX-compliant archives.

s

Force regeneration of archive symbol table (useful after running strip).

S

Do not regenerate symbol table.

u

Use with r to replace only files that have changed since being put in archive.

v

Verbose; print a description of actions taken.

V

Print version number.

Example

Replace mylib.a with object files from the current directory:

ar r mylib.a `ls *.o`


22. arch


arch

Print machine architecture type to standard output. Equivalent to uname -m.

 


23. arecord


arecord [options] [filename]

Records sound using ALSA. Accepts the same arguments and options as aplay.

 


24. arecordmidi


arecord [options] [filename]

Records midi files using ALSA. You must specify the port using the -p flag.

Options

-p,–port=host:port

Set the sequencer host and port used. The default host is the local host, and the default is port 0.

-h,–help

Display help message.

-v,–version

Display version number.

-l, –list

List available ports.

-b,–bmp=n

Set the tempo value to n beats per minute. The default is 120.

-f,–fps=n

Set timing (SMPTE resolution) to n frames per second. The value is normally 24, 25, 29.97 (NTSC dropframe), or 30.

-t,–ticks=n

Set the frequency with which timestamps, or ticks, are used in the file. For MIDI files using musical tempo, timestamps are set in ticks per beat (default 384), while those with SMPTE timing use ticks per frame (default 40).

-s,–split-channels

For each channel of input, create a separate track in the MIDI output file.

 


25. arp


arp [options]

TCP/IP command. Clear, add to, or dump the kernel’s Address Resolution Protocol (ARP) cache (/proc/net/arp). ARP is used to translate protocol addresses to hardware interface addresses. Modifying your ARP cache can change which interfaces handle specific requests. ARP cache entries may be marked with the following flags: C (complete), M (permanent), and P (publish). While arp can create a proxy for a single system, subnet proxies are now handled by the arp kernel module, arp(7). See the “Linux 2.4 or later Advanced Routing HOWTO” for details.

Options

host option arguments may be given as either a hostname or an IP address. With the -D option, they may also be given as a hardware interface address (e.g., eth0, eth1).

-a [hosts] , –display [hosts]

Display entries for hosts or, if none are specified, all entries.

-d host [pub] , –delete host [pub]

Remove the specified host‘s entry. To delete a proxy entry, add the pub argument and specify the interface associated with the proxy using -i.

-D, –use-device

Use the hardware address associated with the specified interface. This may be used with -s when creating a proxy entry.

-f file, –file file

Read entries from file and add them.

-H type, –hw-type type, -t type

Search for type entries when examining the ARP cache. type is usually ether (Ethernet), which is the default, but may be ax25 (AX.25 packet radio), arcnet (ARCnet), pronet (PROnet), or netrom (NET/ROM).

-i interface, –device interface

Select an interface. If you are dumping the ARP cache, this option will cause the command to display only the entries using that interface. When setting entries, this will cause the interface to be associated with that entry. If you do not use this option when setting an entry, the kernel will guess.

-n, –numeric

Display host IP addresses instead of their domain names.

-s host hardware-address [netmask mask] [pub] , –set host hardware-address [pub]

Add a permanent entry for host at hardware-address. A hardware-address for type ether hardware is 6 hexadecimal bytes, colon-separated. The pub argument can be used to set the publish flag, creating a proxy entry.

-v, –verbose

Verbose mode.

Examples

Display entry for host eris:

arp -a eris

Set a permanent cache entry for host illuminati, whose hardware address you know:

arp -s illuminati 00:05:23:73:e6:cf

Set an ARP proxy for host fnord using the eth0 interface’s hardware address:

arp -Ds fnord eth0 pub

Remove the fnord ARP proxy:

arp -i eth0 -d fnord pub


26. as


as [options] files


Generate an object file from each specified assembly-language source file. Object files have the same root name as source files but replace the .s suffix with .o. There may be some additional system-specific options.

Options

[ | files]

Read input files from standard input, or from files if the pipe is used.

-a[cdhlmns] [=file]

With only the -a option, list source code, assembler listing, and symbol table. The other options specify additional things to list or omit:

-ac

Omit false conditionals.

-ad

Omit debugging directives.

-ah

Include the high-level source code, if available.

-al

Include an assembly listing.

-am

Include macro expansions.

-an

Suppress forms processing.

-as

Include a symbol listing.

=file

Set the listing filename to file.

–defsym symbol=value

Define the symbol to have the value value, which must be an integer.

-f

Skip whitespace and comment preprocessing.

–fatal-warnings

Treat warnings as errors.

–gstabs

Generate debugging information in stabs format.

–gdwarf2

Generate DWARF2 debugging information.

-o objfile

Place output in object file objfile (default is file.o).

–statistics

Print information on how much time and space assembler uses.

-v

Display the version number of the assembler.

-I path

Include path when searching for .include directives.

-J

Don’t warn about signed overflow.

-R

Combine both data and text in text section.

-W

Don’t show warnings.

-Z

Generate object file even if there are errors.


27. at


at [options] time [date]


Execute commands at a specified time and optional date. The commands are read from standard input or from a file. (See also batch.) End input with EOF. time can be formed either as a numeric hour (with optional minutes and modifiers) or as a keyword. It can contain an optional date, formed as a month and date, a day of the week, or a special keyword (today or tomorrow). An increment can also be specified.

The at command can always be issued by a privileged user. Other users must be listed in the file /etc/at.allow if it exists; otherwise, they must not be listed in /etc/at.deny. If neither file exists, only a privileged user can issue the command.

Options

-c job [job…]

Display the specified jobs on the standard output. This option does not take a time specification.

-d job [job…]

Delete the specified jobs. Same as atrm.

-f file

Read job from file, not from standard input.

-l

Report all jobs that are scheduled for the invoking user. Same as atq.

-m

Mail user when job has completed, regardless of whether output was created.

-q letter

Place job in queue denoted by letter, where letter is any single letter from a-z or A-Z. Default queue is a. (The batch queue defaults to b.) Higher-lettered queues run at a lower priority.

-V

Display the version number.

Time

hh:[mm] [modifiers]

Hours can have one digit or two (a 24-hour clock is assumed by default); optional minutes can be given as one or two digits; the colon can be omitted if the format is h, hh, or hhmm (e.g., valid times are 5, 5:30, 0530, 19:45). If modifier am or pm is added, time is based on a 12-hour clock. If the keyword zulu is added, times correspond to Greenwich Mean Time.

midnight | noon | teatime | now

Use any one of these keywords in place of a numeric time. teatime translates to 4:00 p.m.; now must be followed by an increment (described in a moment).

Date

month num[, year]

month is one of the 12 months, spelled out or abbreviated to its first three letters; num is the calendar date of the month; year is the four-digit year. If the given month occurs before the current month, at schedules that month next year.

day

One of the seven days of the week, spelled out or abbreviated to its first three letters.

today | tomorrow

Indicate the current day or the next day. If date is omitted, at schedules today when the specified time occurs later than the current time; otherwise, at schedules tomorrow.

Increment

Supply a numeric increment if you want to specify an execution time or day relative to the current time. The number should precede any of the keywords minute, hour, day, week, month, or year (or their plural forms). The keyword next can be used as a synonym of + 1:

Examples

In typical usage, you run at and input commands that you want executed at a particular time, followed by EOF.

$ at 1:00 am tomorrow
at> ./total_up > output

at> mail joe < output
at> <EOT> Entered by pressing Ctrl-D
job 1 at 2003-03-19 01:00

The two commands could also be placed in a file and submitted as follows:

&dollar; at 1:00 am tomorrow < scriptfile

More examples of syntax follow. Note that the first two commands here are equivalent:

&dollar; at 1945 December 9
&dollar; at 7:45pm Dec 9
&dollar; at 3 am Saturday

&dollar; at now + 5 hours
&dollar; at noon next day


28. atd


atd options

System administration command. Normally started in a system startup file. Execute jobs queued by the at command.

Options

-b n

Wait at least n seconds after beginning one job before beginning the next job. Default is 60.

-d

Print error messages to standard error instead of using syslog.

-l average

When system load average is higher than average, wait to begin a new job. Default is 0.8.

-s

Process queue once, then exit.


29. atq


atq [options]

List the user’s pending jobs, unless the user is a privileged user; in that case, list everybody’s jobs. Same as at -l, and related to batch and atrm.

Options

-q queue

Query only the specified queue and ignore all other queues.

-v

Show jobs that have completed but have not yet been deleted.

-V

Print the version number.


30. atrm


atrm [options] job [job...]

Delete jobs that have been queued for future execution. Same as at -d.

Options

-q queue

Remove job from the specified queue.

-V

Print the version number and then exit.


31. audiosend


audiosend [email@address]

Send an audio recording as an email from a properly equipped workstation (Sun and Sony, with microphones). After prompting for address, subject, and Cc: fields, the program asks the user to record a message, then allows him to re-record, send, or cancel. audiosend is one of the metamail tools for processing nontext MIME mail messages.


32. aumix


aumix [options]

Audio mixer tool. Run without any options or arguments for an ncurses-based interactive mode.

Options

The first set of options sets the volume level of a channel to a percentage of the maximum. Each channel is represented by a single letter or number: v for overall volume, b for bass, t for treble, s for synthesizer, w for PCM channels, c for CD, m for microphone, i for line in, o for line out, l for the main line, x for imix, and 1, 2, or 3 for lines 1, 2, and 3. Passing q as an argument to any of those flags displays their current status. Passing + or will increase or decrease the channel volume by one, and +n or n will adjust them by n.

For example, aumix -c q -l 10 will display the CD value and set the main line to 10%.

Additional options:

-C filename

Use the color-scheme file specified to determine the appearance of the ncurses interface.

-d devicename

Specify the mixer device to be used. The default is /dev/mixer.

-f filename

Specify a settings file.

-h

Display a help message and quit.

-I

Interactive mode: provides an ncurses-based UI similar to alsamixer.

-L

Load settings from the default .aumixrc file.

-q

Query all devices, and display the results.

-S

Save settings to the default .aumixrc file.


33. autoconf


autoconf [options] [template_file]

Generate a configuration script from m4 macros defined in template_file, if given, or in a configure.ac or configure.in file in the current working directory. The generated script is almost invariably called configure.

Options

-d, –debug

Don’t remove temporary files.

-f, –force

Replace files generated previously by autoconf.

-h, –help

Print help message, then exit.

-i, –initialization

When tracing calls with the -t option, report calls made during initialization.

-o file, –output=file

Save output to file.

-t macro, –trace=macro

Report the list of calls to macro.

-v, –verbose

Verbosely print information about the progress of autoconf.

-B dir, –prepend-include=dir

Prepend directory dir to the search path.

-I dir, –include=dir

Append directory dir to the search path.

-V, –version

Print version number, then exit.

-W category, –warnings=category

Print any warnings related to category. Accepted categories are:

cross

Cross compilation.

obsolete

Obsolete constructs.

syntax

Questionable syntax.

all

All warnings.

no-category

Turn off warnings for category.

none

Turn off all warnings.

error

Treat warnings as errors.


34. autoheader


autoheader [options] [template_file]

GNU autoconf tool. Generate a template file of C #define statements from m4 macros defined in template_file, if given, or in a configure.ac or configure.in file in the current working directory. The generated template file is almost invariably called config.h.in.

Options

-d, –debug

Don’t remove temporary files.

-f, –force

Replace files generated previously by autoheader.

-h, –help

Print help message, then exit.

-o file, –output=file

Save output to file.

-v, –verbose

Verbosely print information about the progress of autoheader.

-B dir, –prepend-include=dir

Prepend directory dir to the search path.

-I dir, –include=dir

Append directory dir to the search path.

-V, –version

Print version number, then exit.

-W category, –warnings=category

Print any warnings related to category. Accepted categories are:

obsolete

Obsolete constructs.

all

All warnings.

no-category

Turn off warnings for category.

none

Turn off all warnings.

error

Treat warnings as errors.


35. automake


automake [options] [template_file]

GNU automake tool. Create GNU standards-compliant Makefile.in files from Makefile.am template files and can be used to ensure that projects contain all the files and install options required to be standards-compliant. Note that Versions 1.4 and 1.6 differ enough that many distributions include an automake14 package for backward compatibility.

Options

-a, –add-missing

Add any missing files that automake requires to the directory by creating symbolic links to automake‘s default versions.

-c, –copy

Used with the -a option. Copy missing files instead of creating symbolic links.

–cygnus

Specifies project has a Cygnus-style source tree.

-f, –force-missing

Used with the -a option. Replace required files even if a local copy already exists.

–foreign

Treat project as a non-GNU project. Check only for elements required for proper operation.

–gnu

Treat project as a GNU project with the GNU project structure.

–gnits

A stricter version of –gnu, performing more checks to comply with GNU project structure rules.

–help

Print help message, then exit.

-i, –ignore-deps

Disable automatic dependency tracking.

–libdir=dir

Used with the -a option. Search in directory dir for default files.

–no-force

Update only Makefile.in files that have updated dependents.

-v, –verbose

List files being read or created by automake.

–version

Print version number, then exit.

-Werror

Treat warnings as errors.


36. autoreconf


autoreconf [options]

GNU autoconf tool. Update configure scripts by running autoconf, autoheader, aclocal, automake, and libtoolize in specified directories and subdirectories. This command is seldom invoked manually. It is usually called automatically from other autoconf tools.

Options

-d, –debug

Don’t remove temporary files.

-f, –force

Remake all configure scripts, even when newer than their template files.

-h, –help

Print help message, then exit.

-i, –install

Add any default files missing from package by copying versions included with autoconf and automake.

-s, –symlink

Used with the -i option. Create symbolic links to default files instead of copying them.

-v, –verbose

Verbosely print information about the progress of autoreconf.

-I dir, –include=dir

Search in directory dir for input files.

-V, –version

Print version number, then exit.

-W category, –warnings=category

Print any warnings related to category. Accepted categories are:

cross

Cross compilation.

obsolete

Obsolete constructs.

syntax

Questionable syntax.

all

All warnings.

no-category

Turn off warnings for category.

none

Turn off all warnings.

error

Treat warnings as errors.


37. autoscan


autoscan [options] [directory]

GNU autoconf tool. Create or maintain a preliminary configure.ac file named configure.scan based on source files in specified directory, or current directory if none given. If a configure.ac file already exists, autoconf will check it for completeness and print suggestions for correcting any problems it finds.

Options

-d, –debug

Don’t remove temporary files.

-h, –help

Print help message, then exit.

-v, –verbose

Verbosely print information about the progress of autoscan.

-I dir, –include=dir

Search in directory dir for input files. Use multiple times to add multiple directories.

-B dir, –prepend-include=dir

Search dir for input files before searching in other directories. Use multiple times to add multiple directories.

-V, –version

Print version number, then exit.


38. autoupdate


autoupdate [options] [file]

GNU autoconf tool. Update the configure template file file, or configure.ac if no file is specified. This command is seldom invoked manually. It is usually called automatically from other autoconf tools.

Options

-d, –debug

Don’t remove temporary files.

-f, –force

Remake all configure scripts, even when newer than their template files.

-h, –help

Print help message, then exit.

-v, –verbose

Verbosely print information about the progress of autoupdate.

-I dir, –include=dir

Search in directory dir for input files.

-V, –version

Print version number, then exit.

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