# A2osX Command Guide ### Updated February 10, 2020 This Guide provides information on all the A2osX commands and utilities. It helps you not only learn the purpose of each command but also what options a command supports and what arguments it either supports or requires. A2osX comes with a variety of system, file, network and data utilities -- what we refer to as external commands. This just means that each of the following commands or utilities is built as a separate BIN or executable file that runs under A2osX. The source for all of these external commands is readily available, so you can make your own or modify these as your needs dictate. >Note: there are some **internal** commands built into the shell (the interactive prompt) such as CD (change directory) or PWD (print working directory). Those commands are discussed in-depth in the **[Shell Developers Guide](.Docs/Shell%20Developers%20Guide.md).** ## System Commands Typically, you will not directly use the System group commands; they are more commonly found in A2osX system scripts such as ./ETC/INIT or they are launched by the A2osX Kernel itself. All of these commands are found in **./SBIN/** letting you know they are special system commands. ### CIFSD cifsd ip|host sharename mountpoint **cifsd** is a utility for mounting CIFS shares as volumes on A2osX. This utility is in development and is targeted for a future release of A2osX. ### GETTY getty [-e] device process **getty**, short for "get tty", is a system process for A2osX that manages physical or virtual terminals (TTYs). When it detects a connection, it prompts for a user name and then loads the system process LOGIN to authenticate the user. Each GETTY process creates a pseudo file such as /DEV/TTY1 or /DEV/TTY2 to allow A2osX pass input/output streams between processes and connected users. If **getty** is called with the **-e** option, it will automatically exit when the user ends their session or disconnects (used by TELNETD). GETTY handles 3 types of connections: * *virtual terminals* presented and controlled by your Apple Screen and Keyboard. One GETTY process serves one virtual terminal. You can configure the number of virtual terminals on your A2osX system using the KCONFIG utility. Please see **[KCONFIG](#kconfig)**. * *serial terminals* (or emulated terminals i.e. a PC running a VT-100 emulator) connected to your Apple via a Super Serial Card. One GETTY process serves one terminal. See the User Guide for setup and configuration information on connecting Physical Terminals. * *internet terminals* connected to your Apple via the internet using the A2osX TCP networking suite. This suite includes a TELNETD server process that listens for requests from the internet and when such a request is initiated, TELNETD will launch a GETTY process to support that user. One GETTY process will launch for each TELNET user and will exit when then user disconnects (the TELNETD process calls GETTY with the -E option). ### HTTPD httpd HTTPD is a server process that listens for incoming requests to server web pages from your A2osX system. It listens for these requests on port 80. This server process is in development and is in fact being used for test purposes only right now. Further document and options will be made available in a future A2osX release. Network services must be started to use this command. ### INITD initd runlevel This is a stub, or a placeholder, for a new routine being added to A2osX. It will replace part of the start up process and allow for different run levels to be initiated included RunLevel 0 or shutdown. Full implementation is targeted for 0.94. ### INSDRV insdrv driver **insdrv**, short for "install driver", is a system process that loads and initializes hardware drivers for A2osX. Drivers are available for the Apple Mouse, Super Serial Card, and a range of Ethernet cards. Please see the Hardware section of the User Guide for more complete information on the drivers available for A2osX and enabling them in your system. ### KCONFIG kconfig ![](../.screen-shots/ScreenShot.KCONFIG.png) **kconfig**, short for "Kernel Configuration" Utility, is a system program that allows the A2osX administrator to configure various settings of their A2osX system. Any changes to your system configuration are stored in A2OSX.KCONFIG located in the root directory of your A2osX installation. When A2osX boots and loads the KERNEL process, it looks for this file, and if not present it initializes the KERNEL with A2osX defaults. In KCONFIG you can set: - Machine Timing, either 60 (Default) or 50Hz. This should match the power/timing of your system. A2osX uses the Apple's VBL signal and this setting to correctly produce 1-Second and 1/10th-Second events which are used to preemptively switch tasks. If this setting does not match your actual machine timing, timing of task switches will be slower/faster by 10-20% but otherwise A2osX should operate normally. - CHRoot to /RAMx, either Disabled (Default) or Enabled. This feature currently not implemented. - Preemptive Mode, either Disabled (Default) or Enabled. See discussion on A2osX Preemptive Mode in the A2osX User Guide. - TTYs, between 1 and 8, default is 2. This is the number of Virtual Terminals configured on your system. Please note, increasing and decreasing the number of virtual terminals can have a significant impact on the amount of memory used by the system, which in turns impacts the amount of free memory available to run your A2osX programs and scripts. - Slots 1-7, Enabled (Default) or Disabled. Certain drivers in A2osX such as the ones for a Super Serial Card (SSC) or Ethernet Card search for a matching hardware device starting in Slot 1. If you disable any of the slots in KConfig, these slots will be skipped in the search during driver load/initialization. One use of this feature, if you have 2 SSCs in your system with the 1 in slot 1 connected to a printer and another in slot 2 connected to a PC for use with ADTPro. Setting Slot 1 to Disabled, will have A2osX skip the card in Slot 1 connected to the printer from being used by the KM.VEDRIVE driver loaded during A2osX startup. ### LOGIN login **login** is a system process for A2osX that authenticates users against the A2osX User Database stored in ./ETC/PASSWD. Once a user is authenticated, **login** then loads the **sh** (./BIN/SH) process passing it the PROFILE script found in the users Home directory. >Note, at the shell prompt you can execute the **login** command which will then ask you for a name/password and create a new user "session" for you as if you are that user. You will have a new shell environment and be placed in that user's home directory. When you type **exit** or press Control-D at the shell prompt, that session will be terminated and you will returned to your original session in tact. ### NETWORKD networkd netlibrary [netlibrary] ... This system command loads one or more libraries providing network services to A2osX applications and utilities such as **telnet**, **telnetd** and **httpd**. Note, the appropriate Ethernet card driver must first be loaded before attempted to load network libraries. In most cases, network services will be started with a script or as part of the boot process that will load the appropriate drivers, libraries and service programs in the right order. Consult the User Guide for more information on A2osX networking. ### TELNETD telnetd [port] **telnetd** is a server process that listens for incoming requests to connect to your A2osX system. By default it listens on Port 23. You can change the Telnet Server port by starting the **telnetd** process and specifying an alternate port. Typically this would be used to get around local firewall or port restrictions such as when you are running your server at home on a DSL or Cable connection and your provider blocks port 23. In addition, if you are running in an environment with only one public IP address and you have another system at that site already running a Telnet server, you can use this option to move your A2osX host to alternate port. When **telnetd** detects an incoming request it starts a **getty** process and creates a virtual internet terminal for the user and begins the **login** process same as the system would for a hardwired terminal. Note **telnetd** requires that you have a supported Ethernet card and have configured your system for a network appropriately. ## BIN/External Shell commands: The BIN or "External" shell commands are the tools used by most users to display and manipulate data stored on their A2osX system. Typical commands allow you to display directory contents (**ls**), display file contents (**cat**), copy files (**cp**), delete files (**rm**), etc. These commands are found in **./bin/** letting you know they are normal user commands. ### BMP2PIX bmp2pix [-v] bmpfile **bmp2pix** is a graphics conversion utility that will make PIX format files from standard PC format BMP graphics files. The PIX format is used by A2osX to display logos and icons. If you specify the **-v** option, **bmp2pix** will output verbose conversion information. ### CAT cat [-a] [-n] [-s] file The **cat** command is used to display the contents of files stored on any ProDOS volume. While the primary use of this tool is to display the contents of TEXT or TXT files, it can be used to display the contents of other files by using the **-a** option, which will substitute non-printable characters with readable and displayable values such as [EOF] for End of File (Hex x04) or [LF] for Line Feed (Hex x0A). In addition you can use the **-n** option to display the listing of a file with line numbers. Lastly the **-s** option can be used to suppress multiple blank lines from being displayed. As an example, if you had a text file called cattext with the following lines: Start of Cattext End of Cattext Then if you executed at the A2osX prompt: /A2OSX/ROOT/$ cat -n cattext You would get: ---------- > 1: Start of Cattext > 2: > 3: > 4: End of Cattext ---------- If you did **cat -n -s cattext** to suppress the extra blank lines you would see: ---------- > 1: Start of Cattext > 2: > 4: End of Cattext ---------- Note that the numbering of the lines didn't change, because that is their true number in f the file, but **cat** removed the redundant blank lines. Whether there are 2 or 200 blank lines in a row, they will be reduced to just 1. ### CHGRP chgrp [-c] [-r] group filespec This command is not currently implemented. ### CHMOD chmod [-c] [-r] mode filespec This command is not currently *fully* implemented. ### CHOWN chown [-c] [-r] owner filespec This command is not currently implemented. ### CHTYP chtyp [-c] [-r] type filespec This utility allows you to change the type of a file to a standard files types such as SYS or TXT or to any 2-byte hex code. ### CMP cmp [-v [-a]] file1 file2 [skip1 [skip2]] **cmp** will compare two files to determine if they are byte for byte equal. If the files are equal **cmp** exits normally with an exit code of 0. If the files have one or more bytes that are different, **cmp** will exit with an application error code of 224 (Hex $E0). By using the Verbose option you can see the offset and values of the first different byte. With the Verbose and All options you can see the list of all offsets and values that are different. The SKIP options allow you specify a number of bytes to skip in the file(s) before starting the comparison. **cmp** A B 100 200 would skip to the 100th byte of A and the 200th byte of B before starting the byte by byte comparison. Note then that B would need to be 100 bytes larger then A for the comparison to ever end without error. ### CP cp [-c] [-q] [-r] [-y] sourcefilespec [destinationfilespec] The copy command, **cp**, is one of the most powerful commands in A2osX. Not only can it copy files from one ProDOS volume to another, it can copy entire directories or even directory trees from volume to volume, or to another location on the same volume. This recursive nature allows you to use a single command to copy the contents of an entire ProDOS volume with a single command. The **cp** command also supports wild cards so that you can copy just those files matching a pattern. Normally **cp** displays each file name being copied. With the Quiet option (**-q**), this output is suppressed. The Quiet option may be helpful in scripts where maintaining control of the display is important. Normally, when **cp** copies file, it checks to see if a file already exists in the destination, and if so, it prompts the user to ensure they want to overwrite the existing file. With the No Prompt option (**-y**), **cp** will automatically overwrite any existing files. With the Continue option (**-c**), **cp** will continue processing other files in a filespec (i.e. * or file???x) when it encounters an error such as a locked file. ### CSH csh cscript **csh** is one of the interactive and script processing shells under development for A2osX. The **csh** is similar to the C Shell in Linux and uses the C syntax structure for scripting. This shell is under development. A **csh** Shell Developers Guide will be available when a release candidate for this shell becomes available. ### CUT cut [ [[-f field] [-s char]] | [-m column] [-n column] ] cmd | cut [ [[-f field] [-s char]] | [-m column] [-n column] ] The **cut** command is used to extract a sub-part or portion of a string. Use this command to simply extract sub-strings much like Basic's MID, LEFT, or RIGHT might be used. It can also be used within the powerful FOR NEXT construct to process fields of columns from files or the output of processes. If you execute **cut** with no options it will simply pass through all input to the output. To be useful you must use either the field (**-f**) or column (**-m and -n**) switches. With the field switch, you tell **cut** which separated column of text to return. By default fields are separated by spaces, but you can change this to another character with the separator switch (**-s**). The other option is to use the column switches to denote the start (**-m**) and stop (**-n**) column to return. As an example, normally when you execute the **ls -l /** command you get output similar to: ---------- > /A2OSX.BUILD/ROOT/$ LS -L / > /RAM3 S3D2 Blocks Used:8 Total:16000 > /A2OSX.BUILD S7D1 Blocks Used: 3230 Total:65535 > /MAKE S7D2 Blocks Used:48946 Total:65535 ---------- Now, if instead we execute the follow command at the shell prompt: ---------- > /A2OSX.BUILD/ROOT/$ FOR F IN `LS -L /`;ECHO $F;NEXT > /RAM3 S3D2 Blocks Used:8 Total:16000 > /A2OSX.BUILD S7D1 Blocks Used: 3230 Total:65535 > /MAKE S7D2 Blocks Used:48946 Total:65535 ---------- It looks like the same results, but instead of LS simply outputting all of its results at once, each line is being passed to the FOR loop (as VAR $F) where we simply ECHO it. Now imagine if instead we passed $F to CUT, we can display only specific columns of information as seen in these two examples: ---------- > /A2OSX.BUILD/ROOT/$ FOR F IN `LS -L /`;CUT -M 00 -N 15 $F;NEXT > /RAM3 > /A2OSX.BUILD > /MAKE > > /A2OSX.BUILD/ROOT/$ FOR F IN `LS -L /`;CUT -M 17 -N 21 $F;NEXT > S3D2 > S7D1 > S7D2 ---------- ### EDIT edit file ![](../.screen-shots/ScreenShot.EDIT.png) The **edit** command allows the user to interactively read and edit standard text files in A2osX. If you do not specify a file name on the command line, you will be prompted to enter one when you save your work (control-S). Consult the help screen below for a list of the special keys that can be used while editing a file. ![](../.screen-shots/ScreenShot.EDIT%20Help.png) >A note for the touch typists!: While **edit** is not a word processor, it still is one of the most complex programs included in A2osX. It does a lot! A side affect of this, and due to the lack of a keyboard buffer in the Apple //e, if you try to speed type while using EDIT some keystrokes may be dropped. This is most noticeable when using the AppleWin emulator set to 1.0 speed. Changing the emulator speed to at least 2.0 will significantly reduce or eliminate the dropped keys. ### FORMAT format -b blocks [-L] [-1|-2|-3|-4|-5|-6|-7|-8|-9] The **format** command will erase an existing volume and update its name to the VOLUME.NAME supplied. **format** does not currently support low level formatting. The Volume/Device to be formatted must already be formatted. Specifically this means that **format** cannot format a new (never been formatted) floppy disc. Use the -B option to force a block count to format. This is useful in AppleWin because of its non-standard implementation of SmartPort on Slot 7. ### GREP grep [-i] [-n] pattern file command | grep [-i] [-n] pattern The GREP command parses multiple lines of input (either from a file or from the redirected output of another command) and only outputs those lines that contain the PATTERN. In this way, you can think of the GREP command as a filter. You can use the -I option to force GREP to ignore case in the PATTERN and the INPUT lines (i.e. it capitalizes both the source and the PATTERN before doing the compare) though it still outputs the actual lines of content that match (their original capitalization is preserved). The Print Line switch (**-n**) will print number for the lines that match the pattern. Example > /A2OSX.BUILD/ROOT/$ LS -L / | GREP S7 > /A2OSX.BUILD S7D1 Blocks Used: 3230 Total:65535 > /MAKE S7D2 Blocks Used:48946 Total:65535 In this example, only those volumes that are attached to Slot 7 are listed. ### KILL kill [-0|-1|-2] pid The KILL command kills or terminates a running process. This can be most useful when you have a running process that is stuck (perhaps you are debugging a program or script). Switch to another virtual terminal (by pressing Open Apple-1) and executing the PS command to list currently running processes. Then execute the KILL command on + the errand process by its PID found in the displayed process list (i.e. KILL 27 to terminate process with a PIP of 27). Consult the A2osX User Guide for information on using and switching between virtual terminal sessions on your Apple. The optional switches change the type of kill signal sent to the process being killed (-0 for No Signal, -1 for SIGQUIT and -2 for SIGKILL). ### LS ls [-a] [-c|-f|-l] [-r] filespec ![](../.screen-shots/ScreenShot.LS.png) The LS command is probably the most used and useful of all commands available to the A2osX user. **ls** allows you to list the names of the files and directories in the current or specified directory. If supplied with the all check (**-a**) **ls** will include the special directories **.** and **..**. The recurse check (**-r**) tells **ls** to list files and directories of any directory listed (recursively). The display checks (**-c -f and -l**) tell **ls** change the format of the display to a single column of just file/directory names (**-c**), to a single column that includes full paths (**-f**) or a listing with extended file information (**-l**) which includes file ownership, permissions, date/time, etc.. You can pass the **ls** command a *filespec* that includes a directory name and or wild card spec for filtering the listing. For example the command `LS ../MYDIR/FT*` would only list files that begin with FT and are found in the MYDIR sub directory of the parent of the current directory. ### LSDEV lsdev ![](../.screen-shots/ScreenShot.LSDEV.png) Displays a listing of the currently defined devices in the running A2osX system as seen in the screenshot below. ### LSOF lsof Displays a listing of the currently open files in a running A2osX system. This utility is particularly useful to run from another virtual terminal (TTY). Consult the A2osX User Guide for information on using and switching between virtual terminal sessions on your Apple. ### MD5 md5 -d string | file This utility will generated an MD5 hash on a file or on the text string passed with the -D option. ### MEM mem The MEM command displays the available memory and other stats of the Main, Aux and Kernel memory spaces. ### MKDIR mkdir dirname MKDIR will create a new empty directory based on the filespec. If a simple filespec is provided (i.e. mydir or test1) a new directory of that name will be created in the current directory. Optionally, you can pass a fully qualified or relative filespec such as ../../mmdir in which case a new empty directory will be created called **mmdir** and placed in the current directory's parent parent. ### MORE more [-n] [-p] [-s] file command | more [-n] [-p] [-s] The **more** utility allows you to scroll through the output of a file or command one screen full or line at a time. You can use **more** on existing text files, or in conjunction with the PIPE facility (\|) you can direct the output of a command or script to **more** to page through that output. This can be very useful for long directory listings `ls -l | more`. The number switch (**-n**) tells more to number the lines of output. By default, **more** appends its output to the screen a line at a time, which eventually causes the screen to scroll up for each new line. With the page switch (**-p**) **more** will first clear the screen for each page and fill down, eliminating scrolling. By default, **more** strips any TERM (vt100 escape codes) from the output but using the **-s** switch, **more** will send these codes through. ### MV mv [-c] [-q] [-r] [-y] filespec destination The MV command moves files (and directories) from one directory of an A2osX file system to another directory on that same or a different file system. MV like the CP command can operate on a single file, a set files using wildcards, a directory or entire directory tree with the Recurse option (-R). Unlike CP, MV does not just copy files to the new destination it removes them from the source once the copy has been completed. If you are copying an entire directory structure using the Recurse option, MV will not only copy all the files it will create the necessary directories as well and then delete both the source files and directories. Be sure that your destination has sufficient space to hold the files as running out of space mid-copy could result in the directory tree you are attempting to move becoming split between the old and new location. Normally MV displays each file name being moved. With the Quiet option (-Q), this output is suppressed. The Quiet option may be helpful in scripts where maintaining control of the display is important. -y dont prompt for overrides and -c automatically continue on errors such as locked files. ### NSCUTIL nscutil [yy/mm/dd,hh:mm:ss] NSCUTIL is a tool for setting the time of a No Slot Clock or DL1216E. ### PAK pak [-a] [-r] archive filespec **pak** is a utility for combining multiple files into a single compact archive. Use the **unpak** utility to separate the files back out. **pak** is great for software distribution and installation as it allows the developer to gather up all the files that make up an application into a single distributable archive. ### PS ps The **ps** command will list the currently running processes on your A2osX system. This is particularly helpful if you need to stop a process that is stuck. See the **kill** command. ### RM rm [-c] [-q] [-r] filespec The **rm** command removes or deletes files from an A2osX file system. **rm**, like the **cp** command, can operate on a single file, a set files using wild cards, a directory or entire directory tree with the Recurse option (**-r**). Normally **rm** displays each file name being deleted. With the Quiet option (**-q**), this output is suppressed. The Quiet option may be helpful in scripts where maintaining control of the display is important. ### SH sh **SH** is one of the interactive and script processing shells under development for A2osX. The SH shell is similar to the BASH Shell in Linux and uses primarily the BASH syntax structure for scripting. A SH Shell Developers Guide is available in the Documentation Library of A2osX. ### TERM term The **TERM** command is used to start an interactive terminal (VT100) session using an available serial device. You must pass to **term** a valid device name (in lower case) in the form of /dev/comX where X is the slot number of your super serial card. You must have already installed the device driver for this card using the **INSDRV** command and specifying the **SSC.I.DRV**. When you execute the **insdrv ssc.i.drv** command it will search for an available (not used by another process) super serial card and will return to you the name of device installed (i.e. **com2**). Once you start a **TERM** session, you can disconnect from the remote host and return to the shell prompt by pressing Control-T. If you have more then one Apple running A2osX, you could set up one as a host with an SSC that has the right driver installed and a GETTY set for that device (see the User Guide) and then use the other Apple with an SSC to connect to the first one using **TERM**. ### UNPAK unpak **UNPAK** is a utility for extracting files from an A2osX archive created with the **PAK** utility (See PAK above). ### USERADD useradd [-c comment] [-d dir] [-p password] [-s shell] username The **useradd** command is used to add a new User ID and Password to the A2osX User Database. Optionally you can all supply a Command, Home Directory and preferred Shell for the User. Please see the User Guide for more information on User Management. The comment switch (**-c**) allows you to specify additional information about the user being added, typically their full name. The directory switch (**-d**) allows you to specify the users home directory. The password switch (**-p**) allows you to specify the users password which will be encrypted. The shell switch (**-s**) allows you to specify the users default shell program, which for now should be **/bin/sh**. ### USERDEL userdel [-r] username The **userdel** command is used to delete a User ID from the A2osX User Database. Optionally you can have **userdel** remove the users Home directory and any files contained therein. Please see the User Guide for more information on User Management. ### WC wc [-c] [-l] [-m] [-r] [-w] filespec The **wc** command is used to display the char, line and word counts of one or more files. If more then one file is processed then a total count of all files is also displayed. If you use any of the count switches (**-l -m and/or -w** {line, char and word respectively}) then **wc** will only display the counts for the options specified. For example if you use **-l** then only the line count will be display, while using **-l and -w** will display line and word counts, omitting the char count. ### WHO who The **who** command displays a list of users currently logged into the A2osX system and which device they are using to connect to the system. ## Network Tools The Network Tools group of commands allow you to load or start networking services, option IP addresses, connect to other systems, or get the status of your network. Some of these commands are designed specifically as user programs such as Telnet to interactively connect to another computer such as a BBS. Others are intended to be used by system scripts for loading and initializing the network, though they can be run on the command line and therefore are explained here. These commands are found in **./bin/** letting you know they are user commands. ### ARP arp [ip [mac]] The **arp** command displays the current ARP cache and can be used to setup a static ARP entry. When adding an entry, *ip* is a standard IP4 address such as *10.0.0.77* and *mac* is a full MAC address in the form 00:00:00:00:00:00 where each 00 can be any hex value from 00 to FF. Network services must be started to use this command. ### DNSINFO dnsinfo [host ip] The **dnsinfo** command can display the current DNS cache or setup a new static DNS entry. When adding an entry, *host* is typically a fully qualified domain name such as *server.acme.com** and *ip* is a standard IP4 address such as *10.0.0.77*. Network services must be started to use this command. If you run this command for a *host* with an *ip* Address, you can run the command again for the same *host* but with a new *ip* address and the DHS table will be updated appropriately. Note, once you add a *host* to the DNS table this way, you must reboot your system to clear the entry from memory. ### HTTPGET httpget ip|host [port] -u url | -f file The **httpget** command is a utility for retrieving a network page or message from a specified host/URL. Network services must be started to use this command. You must specify a Url to retrieve either with the **-u** switch or in a text file specified with the **-f** switch. Without a Url you will likely get a standard 404 looking web page returned as the result of this command. Typically you would use a command line like the following for **httpget**: HTTPGET www.a2osx.com -U index.html ### IPCONFIG ipconfig [-d|-e|-s] ![](../.screen-shots/ScreenShot.IP1.png) The **ipconfig** command will display the current network configuration for your system. In some cases, if the network drivers and libraries are loaded but not configured, **ipconfig** may configure your system by obtaining (through DHCP) or setting (statically through config files) your IP address and other settings. Optionally you can force a set/reset of your configuration. If Network services are not started when you use this command, an error message will be displayed saying that TCP/IP is not bound to any device. ### NETSTAT netstat The **netstat** command displays the current socket status of your A2osX system. Network services must be started to use this command. **netstat** will show the Type, Protocol, Local Port, Remote IP and Port as well as the status of any current connection. ### PING ping [-1|-2|-3|-4|-5|-6|-7|-8|-9] ip|host The **ping** command is a utility for testing that the IP network services are working, connected to the network and can reach the specified hosts. **ping** can be used to both test your A2osX network setup as well as to ensure that the desired end point is online. Network services must be started to use this command. By default, **ping** continues to run until stopped by pressing the break key (Control-C). Alternatively you can tell **ping** to limit the amount of ping attempts by using the single digit numerical switches shown above. ### TELNET telnet ip|host [port] The **telnet** command is a complete communications/terminal program for connecting to and interacting with foreign hosts using A2osX IP network services. **telnet** can be used to connect to Linux/UNIX systems, Windows hosts or even 8-bit BBS systems as long as they support the standard Telnet protocol. Please note that **telnet** does not support SSH or anytime of secure connection model that are the default mode in most newer systems. Network services must be started to use this command. ## Developer Tools While almost every command and program that comes with A2osX can be considered a developer tool, there are a few that are very specifically created to be used for developer. This section discusses those tools. ### ASM asm file **asm** is A2osX's table driven multi-pass macro assembler. This assembler is still in development and will be released shortly. Technical documentation for the assembler and its language can be found in **[ASM](./ASM.md)**. A Guide to using asm is forthcoming. ### MEMDUMP memdump ![](../.screen-shots/ScreenShot.MEMDUMP.png) **memdump** is a program that allows the developer to display the contents of all of the memory that A2osX is currently using to aide with the debugging of your programs. Lines displayed in inverse indicate memory associated with processes no longer running (dead or abandoned memory, could be caused by program crash). ## License A2osX is licensed under the GNU General Public License. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. The full A2osX license can be found **[Here](../LICENSE)**. ## Copyright Copyright 2015 - 2020, Remy Gibert and the A2osX contributors.