Thanks for reminding. I do, but this would be achieved by the subsequent paste. In my comment, I just rewrote three commands of the pipe (cat/grep/grep) into a single one. Applying this to the whole solution - given the other comments on this topic - is trivial.
I have Parent script that will execute a child script. The child script will take about 2 hours to run and I wanted to somehow build a logic for parent.sh to wait and perform ps -ef|grep cp|grep -v on the child.sh cp process and loop and check return code of child.sh $? as well. Once they are both... (3 Replies)
I 'm new to unix shell scripting can some one guide me to any e-book or link from where i can learn unix shell scripting .. i want to learn create interactive scripts for my day to day solaris work. Any help would be appreciated (1 Reply)
I am comfortable with shell scripting. I need a better logic for below,
I've a reference file, to take the parameter value. For example in the no of channel is 6 i have get the commands as written below. I need need a differenct logic to extract the commands.
NO_OF_CHANNEL=6
case... (3 Replies)
hi experts,
i m a btech student......my mini project is making a secure unix shell which is intented to stop mal practice in educational environment...........in other words need to create a new shell in which commands like cp do not work....can anyone suggest me how to begin with it....refrence... (3 Replies)
Hello Experts,
I have the following questions to be discussed here at this esteemed discussion forum.
I have two Excel sheets which contain Unix Commands llike creating directory the structure/ftp/Copy/Zip etc to basically create an environment. I need help in understanding some of... (1 Reply)
I'm sorry if this doesn't go here, but I'm in depserate need of help with my last unix homework.
Anyways, I'm taking summer classes, and one of them is UNIX. I've understood everything thus far, but I'm having a killer time with how my instructor has worded the problems for shell scripting. I... (3 Replies)
Discussion started by: dw15
3 Replies
LEARN ABOUT LINUX
unbuffer
UNBUFFER(1) General Commands Manual UNBUFFER(1)NAME
unbuffer - unbuffer output
SYNOPSIS
unbuffer program [ args ]
INTRODUCTION
unbuffer disables the output buffering that occurs when program output is redirected from non-interactive programs. For example, suppose
you are watching the output from a fifo by running it through od and then more.
od -c /tmp/fifo | more
You will not see anything until a full page of output has been produced.
You can disable this automatic buffering as follows:
unbuffer od -c /tmp/fifo | more
Normally, unbuffer does not read from stdin. This simplifies use of unbuffer in some situations. To use unbuffer in a pipeline, use the
-p flag. Example:
process1 | unbuffer -p process2 | process3
CAVEATS
unbuffer -p may appear to work incorrectly if a process feeding input to unbuffer exits. Consider:
process1 | unbuffer -p process2 | process3
If process1 exits, process2 may not yet have finished. It is impossible for unbuffer to know long to wait for process2 and process2 may
not ever finish, for example, if it is a filter. For expediency, unbuffer simply exits when it encounters an EOF from either its input or
process2.
In order to have a version of unbuffer that worked in all situations, an oracle would be necessary. If you want an application-specific
solution, workarounds or hand-coded Expect may be more suitable. For example, the following example shows how to allow grep to finish pro-
cessing when the cat before it finishes first. Using cat to feed grep would never require unbuffer in real life. It is merely a place-
holder for some imaginary process that may or may not finish. Similarly, the final cat at the end of the pipeline is also a placeholder
for another process.
$ cat /tmp/abcdef.log | grep abc | cat
abcdef
xxxabc defxxx
$ cat /tmp/abcdef.log | unbuffer grep abc | cat
$ (cat /tmp/abcdef.log ; sleep 1) | unbuffer grep abc | cat
abcdef
xxxabc defxxx
$
BUGS
The man page is longer than the program.
SEE ALSO
"Exploring Expect: A Tcl-Based Toolkit for Automating Interactive Programs" by Don Libes, O'Reilly and Associates, January 1995.
AUTHOR
Don Libes, National Institute of Standards and Technology
1 June 1994 UNBUFFER(1)