The shell tries to open the pipe before it puts the command in background, and freezes waiting for it. You have to put it in a separate subshell to avoid this.
Code:
( command < pipe ) &
Yes, the tee command, I run using & to throw into background.
As I indicated, if you comment out the ls (which seems to have nothing to do with the PIPE - it works fine - no hang.
With the script as is - the first echo makes it into the pipe, the ls works fine - displays to screen only.
then the last echo just hangs. Yes - my script is hanging.
Quote:
What is your goal here, though?
What I'm trying to do:
- want to capture stdout and sterr to both display and log file
- need to capture the return code of the command as well (ie $?) (hence why I'm mucking around with PIPE's so I can displace the tee command).
Hi All,
I am facing a vague issue while trying to make two process talk to each
other using named pipe.
read process
=========
The process which reads, basically creates FIFO using
mkfifo - ret_val = mkfifo(HALF_DUPLEX, 0666);) func.
It then opens the pipe using open func - fd =... (1 Reply)
Hi All,
I am facing a vague issue while trying to make two process talk to each
other using named pipe.
read process
=========
The process which reads, basically creates FIFO using
mkfifo - ret_val = mkfifo(HALF_DUPLEX, 0666) func.
It then opens the pipe using open func - fd = open... (2 Replies)
Gurus,
I've a File Transaction Server, which communicates with other servers and performs some processing.It uses many Named PIPE's.
By mistake i copied a named PIPE into a text file.
I heard that PIPE files shouldn't be copied.Isn't it?
Since it's a production box, i'm afraid on... (2 Replies)
I want to copy the contents of a named pipe to a file. I have tried using:
cat pipe.p >> transcript.log
but I have been unsuccessful, any ideas? (4 Replies)
Hello,
On my machine, all mail is stored in my /var/spool/mail.
IS there a way to direct all mail that goes there into a namep pipe?
Thank you,
Dado (4 Replies)
I would like to pipe (redirect ? - what is the right term?) the output of my script to a file named with the current date.
If I run this at a command prompt:
date +'%Y%m%d"
...it returns "20110429"
OK, that's good... so I try:
./script.sh > "'date +%Y%m%d'.csv"
I get a file... (1 Reply)
Hi,
I want to use a Named pipe to get input from a growing file for further processing. When I prototype this scenario using a while loop, the data is not written to the named pipe.
This the script I use to get data into the Named pipe:
#!/bin/ksh
mkfifo pipe
while (( n <= 10 ))
do
echo... (2 Replies)
Hi,
I am getting data into a Named pipe. Does Named pipe have any size restriction; I know it does not have any storage and it just passes on the data to the next process.
I want to know, if there will be a difference in the Named pipe performance if the data input is more. (I am using DB2... (1 Reply)
Hi All !
I try to collect importent events from syslog and in my
syslog conf, there is something like this:
*.* |/logs/ipes/SLpipe1
I have a program, which opens this pipe and reads the messages from it.
But how this pipe works ? Where can I probably read something about the details,... (3 Replies)
Hi ALL,
How can I test a given file name exists and if it is a named pipe file in shell script ?
Thanks............ (2 Replies)
Discussion started by: mycode.in
2 Replies
LEARN ABOUT OPENDARWIN
script
SCRIPT(1) BSD General Commands Manual SCRIPT(1)NAME
script -- make typescript of terminal session
SYNOPSIS
script [-a] [-k] [-q] [-t time] [file [command ...]]
DESCRIPTION
The script utility makes a typescript of everything printed on your terminal. It is useful for students who need a hardcopy record of an
interactive session as proof of an assignment, as the typescript file can be printed out later with lpr(1).
If the argument file is given, script saves all dialogue in file. If no file name is given, the typescript is saved in the file typescript.
If the argument command ... is given, script will run the specified command with an optional argument vector instead of an interactive shell.
Options:
-a Append the output to file or typescript, retaining the prior contents.
-k Log keys sent to program as well as output.
-q Run in quiet mode, omit the start and stop status messages.
-t time Specify time interval between flushing script output file. A value of 0 causes script to flush for every character I/O event. The
default interval is 30 seconds.
The script ends when the forked shell (or command) exits (a control-D to exit the Bourne shell (sh(1)), and exit, logout or control-d (if
ignoreeof is not set) for the C-shell, csh(1)).
Certain interactive commands, such as vi(1), create garbage in the typescript file. The script utility works best with commands that do not
manipulate the screen. The results are meant to emulate a hardcopy terminal, not an addressable one.
ENVIRONMENT
The following environment variable is utilized by script:
SHELL If the variable SHELL exists, the shell forked by script will be that shell. If SHELL is not set, the Bourne shell is assumed. (Most
shells set this variable automatically).
SEE ALSO csh(1) (for the history mechanism).
HISTORY
The script command appeared in 3.0BSD.
BUGS
The script utility places everything in the log file, including linefeeds and backspaces. This is not what the naive user expects.
It is not possible to specify a command without also naming the script file because of argument parsing compatibility issues.
When running in -k mode, echo cancelling is far from ideal. The slave terminal mode is checked for ECHO mode to check when to avoid manual
echo logging. This does not work when in a raw mode where the program being run is doing manual echo.
BSD June 6, 1993 BSD