09-26-2005
Definitely it does have an impact on CPU usage.
The resources used are in proportion to the complexity of patter.
For eg: for fixed string it will be less. for regular expression it will be more.
To make use of different algorithms for most efficient searches there are seperate binaries itself.
like we have
egrep: extended grep - for regular expression searches
fgrep: fast grep: used for fixed searches across multiple files.
for more information see man pages
thanks,
rishi
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
What would I use to see the CPU usage of my process in Unix? (2 Replies)
Discussion started by: Karen
2 Replies
2. Filesystems, Disks and Memory
hi,
In response to your cpu usage answer
I too read sys/sysinfo.h but , if we put these values to access the repective time fields in the array pst_cpu_time which is a member of the structure pst_dynamic values doesn't seem to match, why is like this? (0 Replies)
Discussion started by: sushaga
0 Replies
3. Programming
how can i monitor usages of CPU, Memory, Hard disk etc. under SUN Solaries
through a c program or java program
i want to store that data into database so i can show it graphically
thanks in advance (2 Replies)
Discussion started by: Gajanad Bihani
2 Replies
4. Programming
Please tell me solaris functions/api for getting following information
1- Function that tells how much memory used by current process
2- Function that tells how much memory used by all running processes
3- Function that tells how much CPU is used by current process
4- Function that tells how... (1 Reply)
Discussion started by: mansoorulhaq
1 Replies
5. HP-UX
how can I find cpu usage memory usage swap usage and
I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times
my final destination is monitor process
logical volume usage above X % and number of Logical voluage above
can I not to... (3 Replies)
Discussion started by: alert0919
3 Replies
6. Solaris
Hi,
I want to monitor the current cpu usage, monitor usage , disk I/o and network utlization for solaris using SNMP.
I want the oids for above tasks.
can you please tell me that
Thank you (2 Replies)
Discussion started by: S_venkatesh
2 Replies
7. Solaris
Hello Friends,
On one of my Solaris 10 box, CPU usage shows 100% using "sar", "vmstat". However, it has 4 CPUs and prstat and glance are not showing enough processes to justify high CPU utilization.
=========================================================================
$ prstat -a
... (4 Replies)
Discussion started by: mahive
4 Replies
8. AIX
How to monitor the IBM AIX server for I/O usage, memory usage, CPU usage, network usage, storage usage? (3 Replies)
Discussion started by: laknar
3 Replies
9. UNIX for Dummies Questions & Answers
guys i need suggestion about how to grep cpu usage and then compare it
example :
if cpu usage <= 40% then print normal and how much cpu usage is
or cpu usage between 40%-65% print normal and much cpu usage is
i've tried like this one but got error
DOMAIN=`uname -n`... (9 Replies)
Discussion started by: ashary
9 Replies
10. UNIX for Dummies Questions & Answers
well i want to get the cpu usage of the current processes.the thing is that i want to list the processes with cpu usage=0 and the others(one list for cpu usage=0 and another for cpu usage>0)..i can list them,but i cant find a way to find the ps with cpu usage=0 and cpu usage>0..pls help me with... (6 Replies)
Discussion started by: strawhatluffy
6 Replies
GREP(1) General Commands Manual GREP(1)
NAME
grep, egrep, fgrep - search a file for a pattern
SYNOPSIS
grep [ option ] ... expression [ file ] ...
egrep [ option ] ... [ expression ] [ file ] ...
fgrep [ option ] ... [ strings ] [ file ]
DESCRIPTION
Commands of the grep family search the input files (standard input default) for lines matching a pattern. Normally, each line found is
copied to the standard output; unless the -h flag is used, the file name is shown if there is more than one input file.
Grep patterns are limited regular expressions in the style of ed(1); it uses a compact nondeterministic algorithm. Egrep patterns are full
regular expressions; it uses a fast deterministic algorithm that sometimes needs exponential space. Fgrep patterns are fixed strings; it
is fast and compact.
The following options are recognized.
-v All lines but those matching are printed.
-c Only a count of matching lines is printed.
-l The names of files with matching lines are listed (once) separated by newlines.
-n Each line is preceded by its line number in the file.
-b Each line is preceded by the block number on which it was found. This is sometimes useful in locating disk block numbers by con-
text.
-s No output is produced, only status.
-h Do not print filename headers with output lines.
-y Lower case letters in the pattern will also match upper case letters in the input (grep only).
-e expression
Same as a simple expression argument, but useful when the expression begins with a -.
-f file
The regular expression (egrep) or string list (fgrep) is taken from the file.
-x (Exact) only lines matched in their entirety are printed (fgrep only).
Care should be taken when using the characters $ * [ ^ | ? ' " ( ) and in the expression as they are also meaningful to the Shell. It is
safest to enclose the entire expression argument in single quotes ' '.
Fgrep searches for lines that contain one of the (newline-separated) strings.
Egrep accepts extended regular expressions. In the following description `character' excludes newline:
A followed by a single character matches that character.
The character ^ ($) matches the beginning (end) of a line.
A . matches any character.
A single character not otherwise endowed with special meaning matches that character.
A string enclosed in brackets [] matches any single character from the string. Ranges of ASCII character codes may be abbreviated
as in `a-z0-9'. A ] may occur only as the first character of the string. A literal - must be placed where it can't be mistaken as
a range indicator.
A regular expression followed by * (+, ?) matches a sequence of 0 or more (1 or more, 0 or 1) matches of the regular expression.
Two regular expressions concatenated match a match of the first followed by a match of the second.
Two regular expressions separated by | or newline match either a match for the first or a match for the second.
A regular expression enclosed in parentheses matches a match for the regular expression.
The order of precedence of operators at the same parenthesis level is [] then *+? then concatenation then | and newline.
SEE ALSO
ed(1), sed(1), sh(1)
DIAGNOSTICS
Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or inaccessible files.
BUGS
Ideally there should be only one grep, but we don't know a single algorithm that spans a wide enough range of space-time tradeoffs.
Lines are limited to 256 characters; longer lines are truncated.
GREP(1)