_p_cmd.txt

一个通讯程序源码

.DE
.DS L
    hexdump -ts 'Example hex dump' %left($s0,9)
Example hex dump
0000  54 68 65 20 71 75 69 63 6B | The quick |
.DE
.DS L
    hexdump -s %left($s0,9)
0000  54 68 65 20 71 75 69 63 6B | The quick |
.DE

.*s 2 "home"

usage: home

This command homes the video cursor.

.*s 2 "icolor"

usage: icolor <int-colors>

This command sets the normal and reverse foreground
and background colors according to <int-colors>, an integer
value in the format as that returned by the
.B %colors
integer function.

This command is provided primarily to be able to save the color
state, modify it temporarily and then restore it.
.DS L
Example:

    mkvar $icolor_save; $icolor_save = %colors
    color red; echo 'Connection seems to be dead'
    icolor $icolor_save # restore previous colors
.DE

.*s 2 "ifi"

.DS L
usage: ifi <int> <rel-op> <int> <statement>
       ifi <int> <rel-op> <int>
           <statement>
       ifi <int> <rel-op> <int>
       {
           any kind or number of statements
       }
.DE

This command selectively executes one or more statements
based on a test of two integer quantities.  See the
description of the
.B break ,
.B continue ,
and
.B else
commmands for examples of how the command is used.

.*s 2 "ifs"

.DS L
usage: ifs <str> <rel-op> <str> <statement>
       ifs <int> <rel-op> <int>
           <statement>
       ifs <int> <rel-op> <int>
       {
           any kind or number of statements
       }
.DE

This command selectively executes one or more statements
based on a test of two string values.  See the
description of the
.B break ,
.B continue ,
and
.B else
commmands
and many other examples throughout the document,
for examples of how the command is used.

.*s 2 "insline"

usage: insline

This command inserts a line onto the video screen at the current line.

.*s 2 "lbreak"

usage: lbreak

This command transmits a break to the remote system.
It is the procedure command analogous to the
.B break
interactive command.

.*s 2 "lgets"

.DS L
usage: lgets [-er] <strvar> <t1-int> <t2-int> [<stop-str>]

-e echo received characters to screen
-r raw read (retain carriage returns)
.DE

This command reads a string from the attached communications
line.
<t1-int> is the number of tenths of seconds before
timing out waiting for the first character to be received.
<t2-int> is the number of tenths of seconds before
timing out on later characters.
<stop-str> is an optional argument, which if received, immediately
terminates the read.
Integer variable $i0 is set to the count of characters received.

If the specified string variable is filled with characters
before the <stop-str> has been encountered or before a timeout
occurs, then the command returns with $i0 set to the maximum
size of the variable.  

Most procedure commands will increase the size of an 
unumbered string variable as needed until the maximum 
string size is reached.
The
.B lgets
command
.I does
.I not .
You must start with the command with a string variable whose maximum size
is already the desired value.
Refer to the section on string variables
above and the section describing the
.B mkvar
command below for information on the size of string variables.

.*s 2 "logevent"

.DS L
usage: logevent <str>
.DE

This command writes a log item to ~/.ecu/log.

.DS L
Example:

    $s0='/tmp/alm.log'
    log 'appending alarm info to '+$s0

writes:
10-02-1989-17:39-01261-PROC appending alarm info to /tmp/alm.log
.DE
assuming the transmitter process pid is 1261 and you are living in
1989.
.*s 2 "lookfor"

.DS L
lookfor [-e] [quiet | <str>] [<timeout-int>]

-e echo to screen while "looking"
.DE
This command is used to read from the attached commuications line
until one of two user-specified conditions occurs.

The 'quiet' option waits for the line to become
quiet for the number of tenths of seconds specified  by <timeout-int>.

The other option reads the line until <str> is read from the line
or until <timeout-int> tenths of seconds elapses.  With this option,
integer variable $i0 is set to 1 if <str> is found within the
timeout period or 0 if not.

.DS L
Examples:

    lookfor -e quiet 20   wait for quiet line for 2 secs
    lookfor 'word:' 50    wait for 'word:' for up to 5 secs
.DE
.*s 2 "mkvar"

.DS L
usage: mkvar [$]i<name>
       mkvar [$]s<name>(<size>)
.DE

This command creates one or more named (temporary)
integer or string variables.
The variable type is determines by the first character
of the variable, which must be 'i' or 's'.  The size of a string
variable must be specified via the <size> argument.  An optional '$'
may be supplies for neatness, but may be omitted if desired.

.*s 3 "Variable Names"

The names for created (named, temporary) variables consist of
a dollar sign ('$'), an 'i' for integer or 's' for string and
up to fifteen characters from the set [A-Za-z0-9_].

The first character after the 'i' or 's' in <name> 
must be non-numeric.  '$sxyz' and '$s_3xyz' are legal, but '$s3xyz'
is not (it would be interpreted as '$s3' followed by the illegal
command sequence 'xyz').

The <name> space for integer and string variables are separate.
It is possible to have an integer variable named '$ixyz' and a string
variable named '$sxyz'.  

.*s 3 "Variable Life and Scope"

The life and scope of created variables is for
the duration of the execution
of the creating procedure.  Procedures called
by the creating procedure (by 'do') can reference
temporary variables declared by a
previous procedure.  When created, integer variables are set
to zero and string variables are set to zero length.
These features differ from numbered variables
which retain their scope and values at all times, even when
procedure execution terminates and ECU returns to interactive mode.

Variables may be created by the same name more than once.
The latest mkvar execution specifies the variable referenced.
Thus if proc1 declares '$ixx' and calls proc2 which also declares '$ixx',
proc2's variable is distinct from proc1's and disappears when proc2
terminates, thus making proc1's available to it again, containing
the same value as it had at the time proc2 was called.

.*s 3 "String Variable Size"

The maximum value for <size> is 16384.
Regardless of the size specified in the creation of a string
variable, ECU will usually expand it's size as necessary up to the
maximum.  Check the documentation for the operation you are
performing; if there is no exception noted, ECU will expand
the string maximum size as necessary.  For instance, the
set command will grow a string as part of assignment.  However,
the
.B lgets
command will not.

.DS L
Examples:

    mkvar i_count
    mkvar $i_count
    mkvar s_20(20),s_80(80),i_timeout,$i_colors
.DE

.*s 2 "nap"

usage: nap <int>
       nap -m <int>

This command suspends procedure execution for <int> tenths of
seconds if 
.B -m
is not specified.
If -m is used, execution is suspended for <int> milliseconds.
Note: the actual period execution is suspended depends, as usual,
on the scheduling load of the system.  For small -m values, be aware
that the granularity of the nap duration is set by the system,
20 milliseconds for XENIX 286 and 386, 10 milliseconds for UNIX.

If you need to know the frequency of the system clock,
something like
.DS L
      $i0 = %stoi(%getenv("HZ"))
.DE
will obtain the value for you (provided HZ is in the process' environment).
.DS L
Examples:

    nap 30
    nap $i0*$i2
	nap -m 50
.DE

.*s 2 "nice"

usage: nice <int>

This command sets the nice value of the process.  It behaves
exactly like the nice(S) or nice(2) system call. The <int> argument
must be in the range 0 through 39, inclusive.  If the call
fails, a warning is printed and the procedure continues to
execute.  The current nice value may be obtained using the
.B %nice
integer function.  See also the description of the
.B nice
interactive command. 

.*s 2 "parity"

.DS L
usage: parity [even | odd | none]
       parity <str>
.DE

This command sets the parity for the attached communications line.
If <str> is supplied, the first character must be 'e', 'o' or 'n'.
Uppercase equivalents are also accepted.

.DS L
Examples:

    parity even
    parity 'e'
    parity 'Even now as we speak'
.DE

.*s 2 "pclose"

usage: pclose <filenum>

This command should be issued when a command started by the
interactive
.B popen
commandf completes.

.*s 2 "plog"

.DS L
usage: plog
       plog <str>
       plog off
.DE

This command controls logging to a file of the screen output during
procedure execution.  With no argument, the command displays the status
of logging.  <str> specifies a log file pathname, while the 'off'
argument turns logging off.

If procedure execution terminates due to an error, procedure logging
is turned off.  However, if procedure execution terminates
normally while logging is active, erratic and unpredictable portions
of interactive mode screen output will continue to be logged to
the current log file.

The interactive mode command
.B plog
may also be used to control procedure logging.
.DS L
Example:

    mkvar s_logname(128)
    $s_logname = %dir+'logname'
    plog $s_logname
    echo 'Test'
    plog off;cd 'somewhere_else';plog $s_logname
    echo 'Test'
.DE

.*s 2 "popd"

.DS L
usage: popd [ | <#> | all]
.DE

This command returns to a previous directory after a
.B pushd
command has been previously executed.

If no argument is supplied, the directory at the immediately previous
level is restored.  

If a numeric argument is supplied, the directory
at the specified level is restored; the level numbers may be obtained by
issuing a
.B pushd
command with no arguments.

If the 'all' argument is supplied, it is treated as a numeric argument of 0;
that is the directory stack is cleared and the directory at level 0 is
restored.

The directory stack is shared between interactive and procedure
commands.  Neither beginning nor ending a procedure affects the
directory stack level.

.DS L
Examples:
   popd
   popd 3
   popd all
.DE

.*s 2 "popen"

usage: popen [-switches] <filenum> <command>

This command executes a shell command defined by the string argument <command>
and associates it with the user-chosen file number <filenum> (which
must be an integer value between 0 and 4, inclusive).

The argument switches govern whether the command is
to receive input from ECU or output to ECU and must be chosen
from this list:
.VL 15 4
.LI -r
The command will output to ECU.
.LI -w
The command will receive input from ECU.
.LE

The switches argument may be omitted; in such cases,
the file is opened as though '-r' had been supplied.  However,
if procedure tracing is enabled (see the description of the
interactive and procedure command
.B ptrace ),
a warning message will be issued.

The command sets $i0 = 0 if successful, else to the
.B errno
from the associated system call (refer to the 
.B %errstr
string function and/or /usr/include/sys/errno.h).
.DS L
Example:

    popen 0 -r 'ls -l *.log'
    popen 1 -w 'cat | sort > /tmp/sorted'
.DE


.*s 2 "prompt"

usage: prompt <str>

This command allows selection of an alternate prompt to the interactive
mode HOME command trigger.
Refer to the section titled "ECUPROMPT"
for more information on the interactive mode prompt.

Note: the interactive and procedure
.B hangup
commands both cause the default prompt to be reestablished.

.DS L
Example:

     prompt %rname+' >'    use remote name in prompt
.DE

.*s 2 "ptrace"

.DS L
usage: ptrace [ <str> | off ]
.DE

This command controls procedure execution tracing.  Trace
output is written to the screen and varys in its nature depending upon
the command being traced.  Specifically, any change to a string or
integer variable is noted.  If tracing is enabled, the output will also
be written to any active procedure log file (see the
.B plog
interactive and procedure commands).

The majority of procedure tracing features use the current trace
state as a binary condition.  That is, either tracing is done
or not.  However, the procedure command
.B expresp
emits varying levels of debugging output in a manner similar to
the uucico -x flag.

.*s 2 "pushd"

.DS L
usage: pushd [ | <dir>]
.DE

This command either 1) saves the current directory pathname on
a stack and establishes a new current directory or
2) displays the current stack and current directory.
The stack size is 10.

If no argument is supplied, the directory stack is displayed.

The directory stack is shared between interactive and procedure
commands.  Neither beginning nor ending a procedure affects the
directory stack level.

.DS L
Examples:
   pushd
   pushd '/tmp'
.DE

.*s 2 "putf"

Not yet implemented.

.*s 2 "return"

usage: return [<int>]

This command serves two functions: to return from a gosub to or
return from a procedure execution.  If <int> is supplied, it must be in the
range 0 to 255.  Other values result in a return value of 255.

If no gosub is active,
.B return
causes the currently executing procedure to terminate,
returning either to a calling procedure or to the interactive mode.
If <int> is supplied and it's value is nonzero, then all procedure execution is
terminated and the integer status is printed
on the screen along with the name of the executing procedure.

If a gosub is active,
.B return
or
.B return
0 causes control to return to the statement immediately following the
.B gosub
which invoked the subroutine.
If <int> is supplied and it's value is nonzero, then all procedure execution is
terminated and the integer status is printed
on the screen along with the name of the executing procedure.

It is not possible to terminate a procedure with normal status from
within a subroutine.

.DS L
Example:

#---------------------
# gosub.ep
#---------------------
    echo 'main'; gosub SUB; echo 'back to main'
    return

SUB
    echo 'sub'
    gosub SUB2
    echo 'back to sub'
    return


SUB2
    echo 'sub2'
    return

.DE

.*s 2 "rk"

usage: rk [-a]

This command invokes C-Kermit to
receive
files. ECU searches the PATH list for 'kermit' or 'ckermit',
expecting to find Columbia University C-Kermit version 5A(173)
or later.  The file ~/.kermrc must be set up to have any desired
initialization parameters you desire (refer to C-Kermit
documentation for more information).
The remote protocol must have been started prior to the
execution of this command.

WARNING: until further notice, avoid suspending Kermit
with ^\Z.  ECU is totally unprepared to act as a job control
process group leader.

If switch '-a'