examples/nsh
^^^^^^^^^^^^
This directory contains the NuttShell (NSH). This is a simple
shell application for NuttX.
- Console/NSH Front End
- Command Overview
- Conditional Command Execution
- Built-In Variables
- Current Working Directory
Environment Variables:
- Simple Commands
- NSH Configuration Settings
Command Dependencies on Configuration Settings
NSH-Specific Configuration Settings
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:
NuttShell (NSH)
nsh>
'nsh>' is the NSH prompt and indicates that you may enter a command
from the console.
Command Overview
^^^^^^^^^^^^^^^^
This directory contains the NuttShell (NSH). This is a simple
shell-like application. At present, NSH supports the following commands
forms:
Simple command: <cmd>
Command with re-directed output: <cmd> > <file>
<cmd> >> <file>
Background command: <cmd> &
Re-directed background command: <cmd> > <file> &
<cmd> >> <file> &
Where:
<cmd> is any one of the simple commands listed later.
<file> is the full or relative path to any writable object
in the filesystem name space (file or character driver).
Such objects will be referred to simply as files throughout
this README.
NSH executes at the mid-priority (128). Backgrounded commands can
be made to execute at higher or lower priorities using nice:
[nice [-d <niceness>>]] <cmd> [> <file>|>> <file>] [&]
Where <niceness> is any value between -20 and 19 where lower
(more negative values) correspond to higher priorities. The
default niceness is 10.
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:
if <cmd>
then
[sequence of <cmd>]
else
[sequence of <cmd>]
fi
Built-In Variables
^^^^^^^^^^^^^^^^^^
$? - The result of the last simple command execution
Current Working Directory
^^^^^^^^^^^^^^^^^^^^^^^^^
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.
Environment Variables:
----------------------
PWD - The current working directory
OLDPWD - The previous working directory
Simple Commands
^^^^^^^^^^^^^^^
o [ <expression> ]
o test <expression>
These are two alternative forms of the same command. They support
evaluation of a boolean expression which sets $?. This command
is used most frequently as the conditional command following the
'if' in the if-then[-else]-fi construct.
Expression Syntax:
------------------
expression = simple-expression | !expression |
expression -o expression | expression -a expression
simple-expression = unary-expression | binary-expression
unary-expression = string-unary | file-unary
string-unary = -n string | -z string
file-unary = -b file | -c file | -d file | -e file | -f file |
-r file | -s file | -w file
binary-expression = string-binary | numeric-binary
string-binary = string = string | string == string | string != string
numeric-binary = integer -eq integer | integer -ge integer |
integer -gt integer | integer -le integer |
integer -lt integer | integer -ne integer
o cat <path> [<path> [<path> ...]]
This command copies and concatentates all of the files at <path>
to the console (or to another file if the output is redirected).
o cd [<dir-path>|-|~|..]
Changes the current working directory (PWD). Also sets the
previous working directory environment variable (OLDPWD).
FORMS:
------
'cd <dir-path>' sets the current working directory to <dir-path>.
'cd -' sets the current working directory to the previous
working directory ($OLDPWD). Equivalent to 'cd $OLDPWD'.
'cd' or 'cd ~' set the current working directory to the 'home'
directory. The 'home' directory can be configured by setting
CONFIG_LIB_HOMEDIR in the configuration file. The default
'home' directory is '/'.
'cd ..' sets the current working directory to the parent directory.
o cp <source-path> <dest-path>
Copy of the contents of the file at <source-path> to the location
in the filesystem indicated by <path-path>
o echo [<string|$name> [<string|$name>...]]
Copy the sequence of strings and expanded environment variables to
console out (or to a file if the output is re-directed).
o exec <hex-address>
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> &'
o exit
Exit NSH. Only useful if you have started some other tasks (perhaps
using the 'exec' command') and you would like to have NSH out of the
way.
o help
Presents summary information about each command to console.
o ifconfig
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.
o ls [-lRs] <dir-path>
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.
o mb <hex-address>[=<hex-value>][ <hex-byte-count>]
o mh <hex-address>[=<hex-value>][ <hex-byte-count>]
o mw <hex-address>[=<hex-value>][ <hex-byte-count>]
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>
o mem
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.
o ps
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>
o ping [-c <count>] [-i <interval>] <ip-address>
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>
o pwd
Show the current working directory.
nsh> cd /dev
nsh> pwd
/dev
nsh>
Same as 'echo $PWD'
nsh> echo $PWD
/dev
nsh>
o set <name> <value>
Set the environment variable <name> to the sting <value>.
For example,
nsh> echo $foobar
nsh> set foobar foovalue
nsh> echo $foobar
foovalue
nsh>
o sh <script-path>
Execute the sequence of NSH commands in the file referred
to by <script-path>.
o sleep <sec>
Pause execution (sleep) of <sec> seconds.
o unset <name>
Remove the value associated with the environment variable
<name>. Example:
nsh> echo $foobar
foovalue
nsh> unset foobar
nsh> echo $foobar
nsh>
o usleep <usec>
Pause execution (sleep) of <usec> microseconds.
NSH 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 README file.
Command Dependencies on Configuration Settings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Command Depends on Configuration
---------- --------------------------
[ !CONFIG_EXAMPLES_NSH_DISABLESCRIPT
cat CONFIG_NFILE_DESCRIPTORS > 0
cd !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0
cp CONFIG_NFILE_DESCRIPTORS > 0
echo --
exec --
exit --
help --
ifconfig CONFIG_NET
ls CONFIG_NFILE_DESCRIPTORS > 0
mb,mh,mw ---
mem ---
mkdir !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0
mkfatfs !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_FAT
mkfifo !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0
mount !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_FAT
ping CONFIG_NET && CONFIG_NET_ICMP && CONFIG_NET_ICMP_PING && !CONFIG_DISABLE_CLOCK && !CONFIG_DISABLE_SIGNALS
ps --
pwd !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0
rm !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0
rmdir !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0
set !CONFIG_DISABLE_ENVIRON
sh CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0 && !CONFIG_EXAMPLES_NSH_DISABLESCRIPT
sleep !CONFIG_DISABLE_SIGNALS
test !CONFIG_EXAMPLES_NSH_DISABLESCRIPT
umount !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_FAT
unset !CONFIG_DISABLE_ENVIRON
usleep !CONFIG_DISABLE_SIGNALS
NSH-Specific Configuration Settings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The behavior of NSH can be modified with the following settings in
the configs/<board-name>/defconfig file:
* CONFIG_EXAMPLES_NSH_FILEIOSIZE
Size of a static I/O buffer used for file access (ignored if
there is no filesystem).
* 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_CONSOLE
If CONFIG_EXAMPLES_NSH_CONSOLE is 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:
* 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.
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