hi. Im trying to install a switch.
And the manual says i should type a command including a SerialPortDevicePath. which is the filepath to serial port used for connection.
However.. nothing about how to find this info.
Could anyone help me where to find this path?
thx
mr.T (6 Replies)
Hey!
I'm trying to figure out a sollution for a problem I have at my company with an Iomega MiniMax 500 GB USB disk.
If i run cat /proc/bus/usb/devices
I get this information:
T: Bus=01 Lev=02 Prnt=04 Port=00 Cnt=01 Dev#= 5 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00... (2 Replies)
Hello!
I am working on an application which reads environmental instruments which have serial ports. The application requires a serial port to be present to talk to the device (i.e. /dev/ttyS0 ). In some instances the environmental devices will be 100's of yards away from the computer, so a... (5 Replies)
I have problem with C programming. I want to send & receive data through serial communication. I send data(command) to device to get data from device but when receive data, it can't get altogether of data.
It get only some data. What should I do to get altogether of data?
If all of... (7 Replies)
I am using the while-loop to read a file.
The file has lines with null-terminated strings (words, actually.)
What I have by that reading - just a first word up to '\0'!
I need to have whole string up to 'new line' - (LF, 10#10, 16#A)
What I am doing wrong?
#make file 'grb' with... (6 Replies)
I am trying to change one of my serial printers from /dev/ttyr002 to /dev/ttyr014:
lpstat -s
device for check3: /dev/ttyr002
device for check4: /dev/ttyr002
I changed the tty setting for check3 in:
/etc/printcap
/var/spool/lp/admins/lp/printers/check3
to /dev/ttyr014
Then I get:... (4 Replies)
I have a script batch_vmdgenpqr.sh which has a problem:
#!/bin/bash
while read line
do
vmd.sh -dispdev text -e vmdgenpqr.tcl -args $line
done<file
The do line calls another program, VMD (called by vmd.sh) and it requires the values from $line, but this is not recognised by... (3 Replies)
Hi All,
Am trying to write wrapper shell/bash script on a utility tool for which i need to pass 2 files as arugment to execute utility tool.
Wraper script am trying is to do with above metion 2 files.
utility tool accepts :
a. userinfo file : which contains username
b. item file : which... (2 Replies)
Heyas
I'm trying to read/display a file its content and put borders around it (tui-cat / tui-cat -t(ypwriter).
The typewriter-part is a 'bonus' but still has its own flaws, but thats for later.
So in some way, i'm trying to rewrite cat using bash and other commands.
But sadly it fails on... (2 Replies)
Hello,
I'm works on Ubuntu server
My goal : I would like to read file line per line, but i want to started at the end of file.
Currently, I use instructions :
while read line;
do
COMMAND
done < /var/log/apache2/access.log
But, the first line, i don't want this. The file is long... (5 Replies)
Discussion started by: Fuziion
5 Replies
LEARN ABOUT LINUX
exec
EXEC(P) POSIX Programmer's Manual EXEC(P)
NAME
exec - execute commands and open, close, or copy file descriptors
SYNOPSIS
exec [command [argument ...]]
DESCRIPTION
The exec utility shall open, close, and/or copy file descriptors as specified by any redirections as part of the command.
If exec is specified without command or arguments, and any file descriptors with numbers greater than 2 are opened with associated redi-
rection statements, it is unspecified whether those file descriptors remain open when the shell invokes another utility. Scripts concerned
that child shells could misuse open file descriptors can always close them explicitly, as shown in one of the following examples.
If exec is specified with command, it shall replace the shell with command without creating a new process. If arguments are specified,
they shall be arguments to command. Redirection affects the current shell execution environment.
OPTIONS
None.
OPERANDS
See the DESCRIPTION.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
None.
ASYNCHRONOUS EVENTS
Default.
STDOUT
Not used.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
If command is specified, exec shall not return to the shell; rather, the exit status of the process shall be the exit status of the program
implementing command, which overlaid the shell. If command is not found, the exit status shall be 127. If command is found, but it is not
an executable utility, the exit status shall be 126. If a redirection error occurs (see Consequences of Shell Errors ), the shell shall
exit with a value in the range 1-125. Otherwise, exec shall return a zero exit status.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
None.
EXAMPLES
Open readfile as file descriptor 3 for reading:
exec 3< readfile
Open writefile as file descriptor 4 for writing:
exec 4> writefile
Make file descriptor 5 a copy of file descriptor 0:
exec 5<&0
Close file descriptor 3:
exec 3<&-
Cat the file maggie by replacing the current shell with the cat utility:
exec cat maggie
RATIONALE
Most historical implementations were not conformant in that:
foo=bar exec cmd
did not pass foo to cmd.
FUTURE DIRECTIONS
None.
SEE ALSO
Special Built-In Utilities
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
online at http://www.opengroup.org/unix/online.html .
IEEE /The Open Group 2003 EXEC(P)