NuttShell (NSH)

Last Updated: November 15, 2008



Table of Contents

1.0 Overview

1.1 Console/NSH Front End

1.2 Command Overview

1.3 Conditional Command Execution

1.4 Built-In Variables

1.5 Current Working Directory

1.6 Environment Variables

1.7 NSH Start-Up Script
2.0 Commands.

2.1 Evaluate Expression (test)

2.2 Concatenate Files (cat)

2.3 Change Current Working Directory (cd)

2.4 Copy Files (cp)

2.5 Copy and Convert Files (dd)

2.6 Echo Strings and Variables (echo)

2.7 Execute User Code (exec)

2.8 Get File Via TFTP (get)

2.9 Exit NSH (exit)

2.10 Show Usage Command Usage (help)

2.11 Show Network Configuration (ifconfig)

2.12 Setup/teardown the Loop Device (losetup)

2.13 List Directory Contents (ls)

2.14 Access Memory (mb, mh, and mw)

2.15 Show Memory Manager Status (mem)

2.16 Show Current Tasks and Threads (ps)

2.17 Create a Directory (mkdir)

2.18 Create a FAT Filesystem (mkfatfs)

2.19 Create a FIFO (mkfifo)

2.20 Create a RAMDISK (mkrd)

2.21 Mount a File System (mount)

2.22 Check Network Peer (ping)

2.23 Send File Via TFTP (put)

2.24 Show Current Working Directory (pwd)

2.25 Remove a File (rm)

2.26 Remove a Directory (rmdir)

2.27 Set an Environment Variable (set)

2.28 Execute an NSH Script (sh)

2.29 Wait for Seconds (sleep)

2.30 Unmount a File System (umount)

2.31 Unset an Environment Variable (unset)

2.32 Wait for Microseconds (usleep)

2.33 Hexadecimal Dump (xd)
3.0 Configuration Settings

3.1 Command Dependencies on Configuration Settings

3.2 NSH-Specific Configuration Settings
Index

1.0 Overview

The examples/nsh sub-directory contains the NuttShell (NSH). NSH is a simple shell application for NuttX.

1.1 Console/NSH Front End

Using settings in the configuration file, NSH may be configured to use either the serial stdin/out or a telnet connection as the console or BOTH. When NSH is started, you will see the following welcome on either console:

nsh> is the NSH prompt and indicates that you may enter a command from the console.

1.2 Command Overview

Simple, Re-directed, and Background Commands. The NuttShell (NSH) is a simple shell application. NSH supports the following commands forms:

Where:

nice'd Background Commands NSH executes at the mid-priority (128). Backgrounded commands can be made to execute at higher or lower priorities using nice:

Where <niceness> is any value between -20 and 19 where lower (more negative values) correspond to higher priorities. The default niceness is 10.

1.3 Conditional Command Execution

An if-then[-else]-fi construct is also supported in order to support conditional execution of commands. This works from the command line but is primarily intended for use within NSH scripts (see the sh commnd). The syntax is as follows:

1.4 Built-In Variables

1.5 Current Working Directory

cd and pwd. All path arguments to commands may be either an absolute path or a path relative to the current working directory. The current working directory is set using the cd command and can be queried either by using the pwd command or by using the echo $PWD command.

1.6 Environment Variables

Environment Variables:

1.7 NSH Start-Up Scrip

NSH Start-Up Script. NSH supports options to provide a start up script for NSH. In general this capability is enabled with CONFIG_EXAMPLES_NSH_ROMFSETC, but has several other related configuration options as described with the NSH-specific configuration settings. This capability also depends on:

Default Start-Up Behavior. The implementation that is provided is intended to provide great flexibility for the use of Start-Up files. This paragraph will discuss the general behavior when all of the configuration options are set to the default values.

In this default case, enabling CONFIG_EXAMPLES_NSH_ROMFSETC will cause NSH to behave as follows at NSH startup time:

Modifying the ROMFS Image. The contents of the /etc directory are retained in the file examples/nsh/nsh_romfsimg.h. In order to modify the start-up behavior, there are three things to study:

  1. Configuration Options. The additional CONFIG_EXAMPLES_NSH_ROMFSETC configuration options discussed with the other NSH-specific configuration settings.
  2. mkromfsimg.sh Script. The script examples/nsh/mkromfsimg.sh creates nsh_romfsimg.h. It is not automatically executed. If you want to change the configuration settings associated with creating and mounting the /tmp directory, then it will be necessary to re-generate this header file using the mkromfsimg.sh script.

    The behavior of this script depends upon three things:

  3. rcS.template. The file examples/nsh/rcS.template contains the general form of the rcS file; configurated values are plugged into this template file to produce the final rcS file.

All of the startup-behavior is contained in rcS.template. The role of mkromfsimg.sh is to (1) apply the specific configuration settings to rcS.template to create the final rcS, and (2) to generate the header file nsh_romfsimg.h containg the ROMFS file system image.

2.0 Commands

2.1 Evaluate Expression (test)

Command Syntax:

Synopsis. These are two alternative forms of the same command. They support evaluation of a boolean expression which sets $?. This command is used most frequently as the conditional command following the if in the if-then[-else]-fi construct.

Expression Syntax:

2.2 Concatenate Files (cat)

Command Syntax:

    cat <path> [<path> [<path> ...]]
    

Synopsis. This command copies and concatentates all of the files at <path> to the console (or to another file if the output is redirected).

2.3 Change Current Working Directory (cd)

Command Syntax:

    cd [<dir-path>|-|~|..]
    

Synopsis. Changes the current working directory (PWD). Also sets the previous working directory environment variable (OLDPWD).

Forms:

    cd <dir-path> sets the current working directory to <dir-path>.
    cd - sets the current working directory to the previous working directory ($OLDPWD). Equivalent to cd $OLDPWD.
    cd or cd ~ set the current working directory to the 'home' directory. The home directory can be configured by setting CONFIG_LIB_HOMEDIR in the configuration file. The default home directory is /.
    cd .. sets the current working directory to the parent directory.

2.4 Copy Files (cp)

Command Syntax:

    cp <source-path> <dest-path>
    

Synopsis. Copy of the contents of the file at <source-path> to the location in the filesystem indicated by <dest-path>.

2.5 Copy and Convert Files (dd)

Command Syntax:

    dd if=<infile> of=<outfile> [bs=<sectsize>] [count=<sectors>] [skip=<sectors>]
    

Synopsis. Copy blocks from <infile> to <outfile>. <infile> or <outfile> may be the path to a standard file, a character device, or a block device. Examples follow:

  1. Read from character device, write to regular file. This will create a new file of the specified size filled with zero.
      nsh> ls -l /dev
      /dev:
       crw-rw-rw-       0 zero
      nsh> dd if=/dev/zero of=/tmp/zeros bs=64 count=16
      nsh> ls -l /tmp
      /tmp:
       -rw-rw-rw-    1024 ZEROS
      
  2. Read from character device, write to block device. This will fill the entire block device with zeros.
    • nsh> ls -l /dev
      /dev:
       brw-rw-rw-       0 ram0
       crw-rw-rw-       0 zero
      nsh> dd if=/dev/zero of=/dev/ram0
      
  3. Read from a block devic, write to a character device. This will read the entire block device and dump the contents in the bit bucket.
    • nsh> ls -l /dev
      /dev:
       crw-rw-rw-       0 null
       brw-rw-rw-       0 ram0
      nsh> dd if=/dev/ram0 of=/dev/null
      

2.6 Echo Strings and Variables (echo)

Command Syntax:

    echo [<string|$name> [<string|$name>...]]
    

Synopsis. Copy the sequence of strings and expanded environment variables to console output (or to a file if the output is re-directed).

2.7 Execute User Code (exec)

Command Syntax:

    exec <hex-address>
    

Synopsis. Execute the user logic at address <hex-address>. NSH will pause until the execution unless the user logic is executed in background via exec <hex-address> &.

2.8 Get File Via TFTP (get)

Command Syntax:

    get [-b|-n] [-f <local-path>] -h <ip-address> <remote-path>
    

Synopsis. Copy the file at <remote-address> from the host whose IP address is identified by <ip-address>.

Other options:

    -f <local-path> The file will be saved relative to the current working directory unless <local-path> is provided.
    -b|-n Selects either binary ("octect") or test ("netascii") transfer mode. Default: text.

2.9 Exit NSH (exit)

Command Syntax:

    exit
    

Synopsis. Exit NSH. Only useful for the serial front end if you have started some other tasks (perhaps using the exec command) and you would like to have NSH out of the way. For the telnet front-end, exit terminates the telenet session.

2.10 Show Usage Command Usage (help)

Command Syntax:

    help
    

Synopsis. Presents summary information about each command to console.

2.11 Show Network Configuration (ifconfig)

Command Syntax:

    ifconfig
    

Synopsis. Show the current configuration of the network, for example:

    nsh> ifconfig
    eth0    HWaddr 00:18:11:80:10:06
            IPaddr:10.0.0.2 DRaddr:10.0.0.1 Mask:255.255.255.0
    

if uIP statistics are enabled (CONFIG_NET_STATISTICS), then this command will also show the detailed state of uIP.

2.12 Setup/teardown the Loop Device (losetup)

Command Syntax 1:

    losetup [-o ] [-r] <dev-path> <file-path>
    

Synopsis. Setup the loop device at <dev-path> to access the file at <file-path> as a block device. In the following example a 256Kb file is created (dd) and losetup is used to make the file accessible as a block device. A FAT file system is created (mkfatfs) and mounted (mount). Files can then be managed on the loop-mounted file.

    nsh> dd if=/dev/zero of=/tmp/image bs=512 count=512
    nsh> ls -l /tmp
    /tmp:
     -rw-rw-rw-   262144 IMAGE
    nsh> losetup /dev/loop0 /tmp/image
    nsh> ls -l /dev
    /dev:
     brw-rw-rw-       0 loop0
    nsh> mkfatfs /dev/loop0
    nsh> mount -t vfat /dev/loop0 /mnt/example
    nsh> ls -l /mnt
    ls -l /mnt
    /mnt:
     drw-rw-rw-       0 example/
    nsh> echo "This is a test" >/mnt/example/atest.txt
    nsh> ls -l /mnt/example
    /mnt/example:
     -rw-rw-rw-      16 ATEST.TXT
    nsh> cat /mnt/example/atest.txt
    This is a test
    nsh>
    

Command Syntax 2:

    losetup d <dev-path>
    

Synopsis. Teardown the setup for the loop device at <dev-path>.

2.13 List Directory Contents (ls)

Command Syntax:

    ls [-lRs] <dir-path>
    

Synopsis. Show the contents of the directory at <dir-path>. NOTE: <dir-path> must refer to a directory and no other filesystem object.

Options:

    -R Show the constents of specified directory and all of its sub-directories.
    -s Show the size of the files along with the filenames in the listing
    -l Show size and mode information along with the filenames in the listing.

2.14 Access Memory (mb, mh, and mw)

Command Syntax:

    mb <hex-address>[=<hex-value>][ <hex-byte-count>]
    mh <hex-address>[=<hex-value>][ <hex-byte-count>]
    mw <hex-address>[=<hex-value>][ <hex-byte-count>]
    

Synopsis. Access memory using byte size access (mb), 16-bit accesses (mh), or 32-bit access (mw). In each case,

    <hex-address>. Specifies the address to be accessed. The current value at that address will always be read and displayed.
    <hex-address>=<hex-value>. Read the value, then write <hex-value> to the location.
    <hex-byte-count>. Perform the mb, mh, or mw operation on a total of <hex-byte-count> bytes, increment the <hex-address> appropriately after each access

Example:

    nsh> mh 0 16
      0 = 0x0c1e
      2 = 0x0100
      4 = 0x0c1e
      6 = 0x0110
      8 = 0x0c1e
      a = 0x0120
      c = 0x0c1e
      e = 0x0130
      10 = 0x0c1e
      12 = 0x0140
      14 = 0x0c1e
    nsh>
    

2.15 Show Memory Manager Status (mem)

Command Syntax:

    mem
    

Synopsis. Show the current state of the memory allocator. For example,

    nsh> mem
      arena:      fe2560
      ordblks:         1
      mxordblk:   fdc3e0
      uordblks:     6180
      fordblks:   fdc3e0
    nsh>
    

Where:

    arena This is the total size of memory allocated for use by malloc in bytes.
    ordblks This is the number of free (not in use) chunks.
    mxordblk Size of the largest free (not in use) chunk.
    uordblks This is the total size of memory occupied by chunks handed out by malloc.
    fordblks This is the total size of memory occupied by free (not in use) chunks.

2.16 Show Current Tasks and Threads (ps)

Command Syntax:

    ps
    

Synopsis. Show the currently active threads and tasks. For example,

    nsh> ps
    PID   PRI SCHD TYPE   NP STATE    NAME
        0   0 FIFO TASK      READY    Idle Task()
        1 128 RR   TASK      RUNNING  init()
        2 128 FIFO TASK      WAITSEM  nsh_telnetmain()
        3 100 RR   PTHREAD   WAITSEM  <pthread>(21)
    nsh>
    

2.17 Create a Directory (mkdir)

Command Syntax:

    mkdir <path>
    

Synopsis. Create the directory at <path>. All components of of <path> except the final directory name must exist on a mounted file system; the final directory must not.

Limited to Mounted File Systems. Recall that NuttX uses a pseudo filesystem for its root file system. The mkdir command can only be used to create directories in volumes set up with the mount command; it cannot be used to create directories in the pseudo filesystem.

Example:

2.18 Create a FAT Filesystem (mkfatfs)

Command Syntax:

Synopsis. Format a fat file system on the block device specified by <path>. NSH provides this command to access the mkfatfs() NuttX API. This block device must reside in the NuttX pseudo filesystem and must have been created by some call to register_blockdriver() (see include/nuttx/fs.h).

2.19 Create a FIFO (mkfifo)

Command Syntax:

Synopsis. Creates a FIFO character device anywhere in the pseudo file system, creating whatever psuedo directories that may be needed to complete the <path>. By convention, however, device drivers are place in the standard /dev directory. After it is created, the FIFO device may be used as any other device driver. NSH provides this command to access the mkfifo() NuttX API.

Example

2.20 Create a RAMDISK (mkrd)

Command Syntax:

Synopsis. Create a ramdisk consisting of <nsectors>, each of size <sector-size> (or 512 bytes if <sector-size> is not specified. The ramdisk will be registered as /dev/ram<n> (if <n> is not specified, mkrd will attempt to register the ramdisk as /dev/ram0.

Example

Once the ramdisk has been created, it may be formatted using the mkfatfs command and mounted using the mount command.

Example

2.21 Mount a File System (mount)

Command Syntax:

Synopsis. The 'm ount' command mounts a file system in the NuttX psuedo filesystem. 'mount' performs a three way associating, binding:

  1. File system. The '-t <fstype>' option identifies the type of file system that has been formatted on the <block-device>. As of this writing, vfat is the only supported value for <fstype>
  2. Block Device. The <block-device> argument is the full or relative path to a block driver inode in the pseudo filesystem. By convention, this is a name under the /dev sub-directory. This <block-device> must have been previously formatted with the same file system type as specified by <fstype>
  3. Mount Point. The mount point, <dir-path>, is the location in the pseudo filesystem where the mounted volume will appear. This mount point can only reside in the NuttX pseudo filesystem. By convention, this mount point is a subdirectory under /mnt. The mount command will create whatever psuedo directories that may be needed to complete the full path but the full path must not already exist.

After the the volume has been mounted in the NuttX pseudo filesystem, it may be access in the same way as other objects in thefile system.

Example

2.22 Check Network Peer (ping)

Command Syntax:

    ping [-c <count>] [-i <interval>] <ip-address>
    

Synopsis. Test the network communication with a remote peer. Example,

    nsh> 10.0.0.1
    PING 10.0.0.1 56 bytes of data
    56 bytes from 10.0.0.1: icmp_seq=1 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=2 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=3 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=4 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=5 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=6 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=7 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=8 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=9 time=0 ms
    56 bytes from 10.0.0.1: icmp_seq=10 time=0 ms
    10 packets transmitted, 10 received, 0% packet loss, time 10190 ms
    nsh>
    

2.23 Send File Via TFTP (put)

Command Syntax:

    put [-b|-n] [-f <remote-path>] -h <ip-address> <local-path>
    

Synopsis. Copy the file at <local-address> to the host whose IP address is identified by <ip-address>.

Other options:

    -f <remote-path> The file will be saved relative with the same name on the host unless <remote-path> is provided.
    -b|-n Selects either binary ("octect") or test ("netascii") transfer mode. Default: text.

2.24 Show Current Working Directory (pwd)

Command Syntax:

    pwd
    

Synopsis. Show the current working directory.

    nsh> cd /dev
    nsh> pwd
    /dev
    nsh>
    

Same as echo $PWD.

2.25 Remove a File (rm)

Command Syntax:

    rm <file-path>
    

Synopsis. Remove the specified <file-path> name from the mounted file system. Recall that NuttX uses a pseudo filesystem for its root file system. The rm command can only be used to remove (unlink) files in volumes set up with the mount command; it cannot be used to remove names in the pseudo filesystem.

Example:

2.26 Remove a Directory (rmdir)

Command Syntax:

    rmdir <dir-path>
    

Synopsis. Remove the specified <dir-path> directory from the mounted file system. Recall that NuttX uses a pseudo filesystem for its root file system. The rmdir command can only be used to remove directories from volumes set up with the mount command; it cannot be used to remove directories from the pseudo filesystem.

Example:

2.27 Set an Environment Variable (set)

Command Syntax:

    set <name> <value>
    

Synopsis. Set the environment variable <name> to the string <value>. For example,

    nsh> echo $foobar
    
    nsh> set foobar foovalue
    nsh> echo $foobar
    foovalue
    nsh>
    

2.28 Execute an NSH Script (sh)

Command Syntax:

    sh <script-path>
    

Synopsis. Execute the sequence of NSH commands in the file referred to by <script-path>.

2.29 Wait for Seconds (sleep)

Command Syntax:

    sleep <sec>
    

Synopsis. Pause execution (sleep) for <sec> seconds.

2.30 Unmount a File System (umount)

Command Syntax:

    umount <dir-path>
    

Synopsis. Un-mount the file system at mount point <dir-path>. The umount command can only be used to un-mount volumes previously mounted using mount command.

Example:

    nsh> ls /mnt/fs
    /mnt/fs:
     TESTDIR/
    nsh> umount /mnt/fs
    nsh> ls /mnt/fs
    /mnt/fs:
    nsh: ls: no such directory: /mnt/fs
    nsh>
    

2.31 Unset an Environment Variable (unset)

Command Syntax:

    unset <name>
    

Synopsis. Remove the value associated with the environment variable <name>. Example:

    nsh> echo $foobar
    foovalue
    nsh> unset foobar
    nsh> echo $foobar
    
    nsh>
    

2.32 Wait for Microseconds (usleep)

Command Syntax:

    usleep <usec>
    

Synopsis. Pause execution (sleep) of <usec> microseconds.

2.33 Hexadecimal dump (xd)

Command Syntax:

    xd <hex-address> <byte-count>
    

Synopsis. Dump <byte-count> bytes of data from address <hex-address>.

Example:

    nsh> xd 410e0 512
    Hex dump:
    0000: 00 00 00 00 9c 9d 03 00 00 00 00 01 11 01 10 06 ................
    0010: 12 01 11 01 25 08 13 0b 03 08 1b 08 00 00 02 24 ....%..........$
    ...
    01f0: 08 3a 0b 3b 0b 49 13 00 00 04 13 01 01 13 03 08 .:.;.I..........
    nsh>
    

3.0 Configuration Settings

The availability of the above commands depends upon features that may or may not be enabled in the NuttX configuration file. The following table indicates the dependency of each command on NuttX configuration settings. General configuration settings are discussed in the NuttX Porting Guide. Configuration settings specific to NSH as discussed at the bottom of this document.

Note that in addition to general NuttX configuation settings, each NSH command can be individually disabled via the settings in the rightmost column. All of these settings make the configuration of NSH potentially complex but also allow it to squeeze into very small memory footprints.

3.1 Command Dependencies on Configuration Settings

Table. Command Dependencies on Configuration Settings

Command Depends on Configuration Can Be Disabled with
[ !CONFIG_EXAMPLES_NSH_DISABLESCRIPT CONFIG_EXAMPLES_NSH_DISABLE_TEST
cat CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_CAT
cd !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_CD
cp CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_CP
dd CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_DD
echo
CONFIG_EXAMPLES_NSH_DISABLE_ECHO
exec
CONFIG_EXAMPLES_NSH_DISABLE_EXEC
exit
CONFIG_EXAMPLES_NSH_DISABLE_EXIT
get CONFIG_NET && CONFIG_NET_UDP && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NET_BUFSIZE >= 5581 CONFIG_EXAMPLES_NSH_DISABLE_GET
help
CONFIG_EXAMPLES_NSH_DISABLE_HELP
ifconfig CONFIG_NET CONFIG_EXAMPLES_NSH_DISABLE_IFCONFIG
losetup !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_LOSETUP
ls CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_LS
mb,mh,mw
CONFIG_EXAMPLES_NSH_DISABLE_MB,
CONFIG_EXAMPLES_NSH_DISABLE_MH,
CONFIG_EXAMPLES_NSH_DISABLE_MW
mem
CONFIG_EXAMPLES_NSH_DISABLE_MEM
mkdir !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_WRITABLE4 CONFIG_EXAMPLES_NSH_DISABLE_MKDIR
mkfatfs !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_FAT CONFIG_EXAMPLES_NSH_DISABLE_MKFATFS
mkfifo CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_MKFIFO
mkrd !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_WRITABLE4 CONFIG_EXAMPLES_NSH_DISABLE_MKRD
mount !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_READABLE3 CONFIG_EXAMPLES_NSH_DISABLE_MOUNT
ping CONFIG_NET && CONFIG_NET_ICMP && CONFIG_NET_ICMP_PING && !CONFIG_DISABLE_CLOCK && !CONFIG_DISABLE_SIGNALS CONFIG_EXAMPLES_NSH_DISABLE_PING
ps
CONFIG_EXAMPLES_NSH_DISABLE_PS
put CONFIG_NET && CONFIG_NET_UDP && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NET_BUFSIZE >= 5581,2 CONFIG_EXAMPLES_NSH_DISABLE_PUT
pwd !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0 CONFIG_EXAMPLES_NSH_DISABLE_PWD
rm !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_WRITABLE4 CONFIG_EXAMPLES_NSH_DISABLE_RM
rmdir !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_WRITABLE4 CONFIG_EXAMPLES_NSH_DISABLE_RMDIR
set !CONFIG_DISABLE_ENVIRON CONFIG_EXAMPLES_NSH_DISABLE_SET
sh CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0 && !CONFIG_EXAMPLES_NSH_DISABLESCRIPT CONFIG_EXAMPLES_NSH_DISABLE_SH
sleep !CONFIG_DISABLE_SIGNALS CONFIG_EXAMPLES_NSH_DISABLE_SLEEP
test !CONFIG_EXAMPLES_NSH_DISABLESCRIPT CONFIG_EXAMPLES_NSH_DISABLE_TEST
umount !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_READABLE3 CONFIG_EXAMPLES_NSH_DISABLE_UMOUNT
unset !CONFIG_DISABLE_ENVIRON CONFIG_EXAMPLES_NSH_DISABLE_UNSET
usleep !CONFIG_DISABLE_SIGNALS CONFIG_EXAMPLES_NSH_DISABLE_USLEEP
xd
CONFIG_EXAMPLES_NSH_DISABLE_XD

1 Because of hardware padding, the actual required packet size may be larger
2 Special TFTP server start-up optionss will probably be required to permit creation of files for the correct operation of the put command.
3 CONFIG_FS_READABLE is not a user configuration but is set automatically if any readable filesystem is selected. At present, this is either CONFIG_FS_FAT or CONFIG_FS_ROMFS.
4 CONFIG_FS_WRITABLE is not a user configuration but is set automatically if any writable filesystem is selected. At present, this is only CONFIG_FS_FAT.

3.2 NSH-Specific Configuration Settings

The behavior of NSH can be modified with the following settings in the configs/<board-name>/defconfig file:

Configuration Description
CONFIG_EXAMPLES_NSH_FILEIOSIZE Size of a static I/O buffer used for file access (ignored if there is no filesystem). Default is 1024.
CONFIG_EXAMPLES_NSH_STRERROR strerror(errno) makes more readable output but strerror() is very large and will not be used unless this setting is y
CONFIG_EXAMPLES_NSH_LINELEN The maximum length of one command line and of one output line. Default: 80
CONFIG_EXAMPLES_NSH_STACKSIZE The stack size to use when spawning new threads or tasks. Such new threads are generated when a command is executed in background or as new TELNET connections are established.
CONFIG_EXAMPLES_NSH_NESTDEPTH The maximum number of nested if-then[-else]-fi sequences that are permissable. Default: 3
CONFIG_EXAMPLES_NSH_DISABLESCRIPT This can be set to y to suppress support for scripting. This setting disables the sh, test, and [ commands and the if-then[-else]-fi construct. This would only be set on systems where a minimal footprint is a necessity and scripting is not.
CONFIG_EXAMPLES_NSH_DISABLEBG This can be set to y to suppress support for background commands. This setting disables the nice command prefix and the & command suffix. This would only be set on systems where a minimal footprint is a necessity and background command execution is not.
CONFIG_EXAMPLES_NSH_MMCSDMINOR If the architecture supports an MMC/SD slot and if the NSH architecture specific logic is present, this option will provide the MMC/SD minor number, i.e., the MMC/SD block driver will be registered as /dev/mmcsdN where N is the minor number. Default is zero.
CONFIG_EXAMPLES_NSH_ROMFSETC Mount a ROMFS filesystem at /etc and provide a startup script at /etc/init.d/rcS. The default startup script will mount a FAT FS RAMDISK at /tmp but the logic is easily extensible.
CONFIG_EXAMPLES_NSH_CONSOLE If CONFIG_EXAMPLES_NSH_CONSOLEis set to y, then a serial console front-end is selected.
CONFIG_EXAMPLES_NSH_TELNET If CONFIG_EXAMPLES_NSH_TELNET is set to y, then a TELENET server front-end is selected. When this option is provided, you may log into NuttX remotely using telnet in order to access NSH.

One or both of CONFIG_EXAMPLES_NSH_CONSOLE and CONFIG_EXAMPLES_NSH_TELNET must be defined. If CONFIG_EXAMPLES_NSH_TELNET is selected, then there some other configuration settings that apply:

Configuration Description
CONFIG_EXAMPLES_NSH_IOBUFFER_SIZE Determines the size of the I/O buffer to use for sending/ receiving TELNET commands/reponses
CONFIG_EXAMPLES_NSH_DHCPC Obtain the the IP address via DHCP.
CONFIG_EXAMPLES_NSH_IPADDR If CONFIG_EXAMPLES_NSH_DHCPC is NOT set, then the static IP address must be provided.
CONFIG_EXAMPLES_NSH_DRIPADDR Default router IP address
CONFIG_EXAMPLES_NSH_NETMASK Network mask
CONFIG_EXAMPLES_NSH_NOMAC Set if your ethernet hardware has no built-in MAC address. If set, a bogus MAC will be assigned.

If CONFIG_EXAMPLES_NSH_ROMFSETC is selected, then the following additional configuration setting apply:

Configuration Description
CONFIG_EXAMPLES_NSH_ROMFSMOUNTPT The default mountpoint for the ROMFS volume is "/etc", but that can be changed with this setting. This must be a absolute path beginning with '/' and enclosed in quotes.
CONFIG_EXAMPLES_NSH_INITSCRIPT This is the relative path to the startup script within the mountpoint. The default is "init.d/rcS". This is a relative path and must not start with '/' but must be enclosed in quotes.
CONFIG_EXAMPLES_NSH_ROMFSDEVNO This is the minor number of the ROMFS block device. The default is '0' corresponding to /dev/ram0.
CONFIG_EXAMPLES_NSH_ROMFSSECTSIZE This is the sector size to use with the ROMFS volume. Since the default volume is very small, this defaults to 64 but should be increased if the ROMFS volume were to be become large. Any value selected must be a power of 2.

When the default rcS file used when CONFIG_EXAMPLES_NSH_ROMFSETC is selected, it will mount a FAT FS under /tmp. The following selections describe that FAT FS.

Configuration Description
CONFIG_EXAMPLES_NSH_FATDEVNO This is the minor number of the FAT FS block device. The default is '1' corresponding to /dev/ram1.
CONFIG_EXAMPLES_NSH_FATSECTSIZE This is the sector size use with the FAT FS. Default is 512.

Index

  • exec
  • exit
  • get
  • Greeting
  • help
  • if-then[-else]-fi
  • ifconfig
  • losetup
  • ls
  • mb
  • mh
  • mw
  • mem
  • mkdir
  • mkfatfs
  • mkfifo
  • mkrd
  • mount
  • nice
  • OLDPWD
  • Overview
  • ping
  • Prompt
  • ps
  • put
  • pwd
  • PWD
  • Re-directed commands
  • rm
  • rmdir
  • set
  • sh
  • Simple commands
  • sleep
  • start-up script
  • test
  • umount
  • unset
  • usleep
  • xd