03-23-2011
@Corona688
Yes, 36 cores (9x4). CPU power not an issue. Regularly running over 30,000 concurrent processes.
Bottleneck on reading large files is invariably the disc system, closely followed by the software. This is where reading moderate size files with "cat" scores over the read function in some unix utilities. I recognise that "cut" is actually one of the better ones.
For the advanced user with large data files I am not averse to using "dd" or "cpio" (or both) to read from the disc in an optimum manner.
On a single core system running ancient unix it was very important to minimise the number of concurrent processes. This is really not the case nowadays unless you happen to be running unix on a home system.
Back to the O/P.
The conventional answer is that running more processes is less efficient. On a modern large system with multiple processors (i.e. the norm) it can be more efficient to run a pipeline of multiple efficient processes than to run a single inefficient process.
The "Useless use of cat" brigade have clearly never used a modern computer where apparent inefficiencies are in fact covered by proper utilisation of the software and hardware as a team.
By applying lateral thought we can deduce that hardware design evolution is actually targetted towards making inefficient processes efficient. We can take advantage of that by tactical use of the previously-inefficent processes.
Nuff said.
Last edited by methyl; 03-23-2011 at 07:07 PM..
Reason: spellin, verbosity
9 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
how do you show just the used disk space. using the cut and df command?? or does anyone have any other suggestions on how to do it a better way? (3 Replies)
Discussion started by: rookie22
3 Replies
2. Shell Programming and Scripting
Hi,
I want to cut from a particular position to a particular position and retain the rest.
I tried this
cut -c31-51 file1.txt > file2.txt
But The characters from the position 31 to 51 were only present in file2.txt.
Is there a way to reverse this i.e to retain the rest except from... (1 Reply)
Discussion started by: ragavhere
1 Replies
3. Shell Programming and Scripting
Gurus,
I need help with the cut command :
I have a file with garbage charaters at the beginning of each record; but these characters are not of the same length;
First record has 3 garbage chars to be removed; rest have 2;
If the length was consistent across all the records, I could have... (3 Replies)
Discussion started by: tru_tell
3 Replies
4. Shell Programming and Scripting
Hi
Can anyone what I am doing wrong while using cut command.
for f in *.log
do
logfilename=$f
Log "Log file Name: $logfilename"
logfile1=`basename $logfilename .log`
flength=${#logfile1}
Log "file length $flength"
from_length=$(($flength - 15))
Log "from... (2 Replies)
Discussion started by: dgmm
2 Replies
5. UNIX for Dummies Questions & Answers
hay
i am trying to get JUST the PID from the ps command.
my command line is:
ps -ef | grep "mintty" | cut -d' ' -f2
but i get an empty line. i assume that the delimiter is not just one space character, but can't figure out what should i do in order to do that.
i know i can use awk or cut... (8 Replies)
Discussion started by: ran ber
8 Replies
6. Shell Programming and Scripting
hi,
i have a file
abc,"an,ab",cde,efg
abc,anab,cde,efg and need to cut the second field so the output should be abc,cde,efg and i have used cut -d',' -f1-1,3- but its giving me
abc,ab",cde,efg
abc,cde,efg (4 Replies)
Discussion started by: ATWC
4 Replies
7. UNIX for Beginners Questions & Answers
I'm a complete beginner in UNIX (and not a computer science student either), just undergoing a tutoring course. Trying to replicate the instructions on my own I directed output of the ls listing command (lists all files of my home directory ) to My_dir.tsv file (see the screenshot) to make use of... (9 Replies)
Discussion started by: scrutinizerix
9 Replies
8. Shell Programming and Scripting
VARIABLE="jhovan 5259 5241 0 20:11 ? 00:00:00 /proc/self/exe --type=gpu-process --channel=5182.0.1597089149 --supports-dual-gpus=false --gpu-driver-bug-workarounds=2,45,57 --disable-accelerated-video-decode --gpu-vendor-id=0x80ee --gpu-device-id=0xbeef --gpu-driver-vendor... (3 Replies)
Discussion started by: SkySmart
3 Replies
9. Shell Programming and Scripting
im currently running the following command to grab all arguments in front of a script, directly from the process table.
# cat /tmp/allmyprocs
ubuntu 9933 27793 0 03:29 pts/0 00:00:00 /bin/sh ./prying.sh
ubuntu 9941 9933 0 03:29 pts/0 00:00:00 sh
ubuntu 9952 9941 0 03:29... (1 Reply)
Discussion started by: SkySmart
1 Replies
vfork(2) System Calls Manual vfork(2)
Name
vfork - spawn new process in a virtual memory-efficient way
Syntax
pid = vfork()
int pid;
Description
The can be used to create new processes without fully copying the address space of the old process, which is inefficient in a paged envi-
ronment. It is useful when the purpose of would have been to create a new system context for an The system call differs from in that the
child borrows the parent's memory and thread of control until a call to or an exit (either by a call to or abnormally.) The parent process
is suspended while the child is using its resources.
The system call returns a value of zero (0) in the child's context and, later, the pid of the child in the parent's context.
The system call can normally be used just like It does not work, however, to return while running in the childs context from the procedure
which called because the eventual return from would then return to a nonexistent stack frame. Be careful, also, to call _exit rather than
exit if you cannot call because exit will flush and close standard I/O channels and thereby cause problems in the parent process's standard
I/O data structures. Even with it is wrong to call exit, because buffered data would then be flushed twice.
Restrictions
To avoid a possible deadlock situation, processes which are children in the middle of a are never sent SIGTTOU or SIGTTIN signals. Rather,
output or ioctls are allowed, and input attempts result in an end-of-file indication.
Diagnostics
Same as for
See Also
execve(2), fork(2), sigvec(2), wait(2)
vfork(2)