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1. Shell Programming and Scripting
I am a scripting noob, and having much trouble getting this script to run correctly. Upon start it should read the home directory and sort the files into a text file. Then have user enter a user name and insert it into line 1 of the same text file. Then have the date insert into the second line of... (8 Replies)
Discussion started by: bbaumg02
2. Shell Programming and Scripting
I have 1 file that has elements as follows. Also the CVR(10) and the word "SAUCE" only appear once in the file so maybe a grep command would work?
CVR( 9) = 0.385E+05, ! VEHICLE
CVR(10) = 0.246E+05, ! SAUCE
CVR(11) = 0.162E+03, ! VEHICLE
I need to extract the... (6 Replies)
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3. Shell Programming and Scripting
I have got an Perl array like:
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4. Shell Programming and Scripting
What is the syntax for if statement using && and || operator?
if && ] ||
here its giving me an error to this if statement
any suggestion?? (2 Replies)
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5. Shell Programming and Scripting
I am having an XML tag like:
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Discussion started by: ss_ss
6. Shell Programming and Scripting
Hi, I hope the title does not scare people to look into this thread but it describes roughly what I'm trying to do. I need a solution in PHP.
I'm a programming beginner, so it might be that the approach to solve this, might be easier to solve with an other approach of someone else, so if you... (0 Replies)
Discussion started by: lowmaster
7. Shell Programming and Scripting
This is the first time playing around with perl and need some help.
Assuming if i have a line of text that looks like this:
Date/Time=Nov 18 17:12:11;Device Name=192.168.1.1;Device IP=192.168.1.1;Device Class=IDS;Source IP=126.96.36.199;Source Name=UNKNOWN;Source Port=1679... (3 Replies)
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8. Shell Programming and Scripting
Hi Every body,
I have file which has enttries, with each 5 entries as a set of entries, I would like to read the file (line by line) and print five entries of a set vertically, the next entry should come in the next line.
I am a
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Discussion started by: aruveiv
9. Shell Programming and Scripting
This is likely to be a dumb one.
How can I use sed to substitute string occurances having it read from an input file and write to this very same file ?
I have a file with lots of occurances of '2006', I want to change it to '2007', but I'd like these changes to be saved on the input file.
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Discussion started by: 435 Gavea
10. UNIX for Advanced & Expert Users
I am trying to merge two large file horizontally using paste command. Every thing is working fine except for time. Its taking lot of time.
Is there any effiecient way of doing the same thing or is there anyway by which I can improve its perfomance programatically?
Yeheya (1 Reply)
Discussion started by: yeheyaansari
FIFO(7) Linux Programmer's Manual FIFO(7)
fifo - first-in first-out special file, named pipe
A FIFO special file (a named pipe) is similar to a pipe, except that it is accessed as part of the file system. It can be opened by multi-
ple processes for reading or writing. When processes are exchanging data via the FIFO, the kernel passes all data internally without writ-
ing it to the file system. Thus, the FIFO special file has no contents on the file system; the file system entry merely serves as a refer-
ence point so that processes can access the pipe using a name in the file system.
The kernel maintains exactly one pipe object for each FIFO special file that is opened by at least one process. The FIFO must be opened on
both ends (reading and writing) before data can be passed. Normally, opening the FIFO blocks until the other end is opened also.
A process can open a FIFO in nonblocking mode. In this case, opening for read-only will succeed even if no-one has opened on the write
side yet, opening for write-only will fail with ENXIO (no such device or address) unless the other end has already been opened.
Under Linux, opening a FIFO for read and write will succeed both in blocking and nonblocking mode. POSIX leaves this behavior undefined.
This can be used to open a FIFO for writing while there are no readers available. A process that uses both ends of the connection in order
to communicate with itself should be very careful to avoid deadlocks.
When a process tries to write to a FIFO that is not opened for read on the other side, the process is sent a SIGPIPE signal.
FIFO special files can be created by mkfifo(3), and are indicated by ls -l with the file type 'p'.
mkfifo(1), open(2), pipe(2), sigaction(2), signal(2), socketpair(2), mkfifo(3), pipe(7)
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-12-03 FIFO(7)