Cero said
In your case the letter "w" was matched zero times.
Actually in my case "w" was matched several times. But "r" was matched as well.
Yes its true when asterik is used in grep it matches the preceding charcter zero or more times.
The documentition should have also mentioned , " the preceding character's position will be matched with any characters from [a-Z] and [0-9] "
a test I did
Here the position of "b" got matched with characters from [a-Z] and [0-9]
hi,
I have this script which gives me the result...
#! /usr/bin/sh
set -x
cd /home/managar
a=1
while true
do
if
then
echo " File log.txt exists in this directory "
exit 0
fi
echo " File has not arrived yes..."
sleep 3
let a=a+1
if
then (1 Reply)
I have written a shell script which looks like below:
grep -v ',0,' ./DATA/abc.001 > ./DATA/abc.mid
egrep $GREPSEARCH ./DATA/ebc.mid > ./DATA/abc.cut
the variable GREPSEARCH has values like the below:
... (3 Replies)
Hi all
Here I came accross a situation which i am unable to reason out...
snippet 1
psg ServTest | grep -v "grep" | grep -v "vi" | awk '{
pgm_name=$8
cmd_name="ServTest"
gsub(/]*/,"",pgm_name)
if(pgm_name==cmd_name) { print "ServTest Present =" cmd_name}
}'... (10 Replies)
Hi,
I am using HP-UX B.11.23 U ia64
I am trying to retrieve files using -mtime option of find command
However I found that -mtime is not giving correct results
Following is the output of commands executed on 03-Dec-2009
It can be seen that -mtime +1 should have returned all... (2 Replies)
I have five classes. 2 composition classes,1 aggregation class and 1 dependency class.I have coded all the classes but one of my test program is not giving me the expected result.I have the following classes:
TimeStamp
Interval (composition of 2 TimeStamps)
TimeSheet ( aggregation of many... (3 Replies)
I use many different machines at work, each with different versions of o/s's and installed applications. Sed in vi is particularly inconvenient in the sense that sometimes it will accept the "\r" as a carriage return, sometimes not. Same thing with "\n". For instance, if I have a list of hosts... (7 Replies)
Hi
I am comparing two files with comm -13 < (sort acc11.txt) < (sort acc12.txt) > output.txt
purpose: Get non matching records which are in acc12 but not in acc11...
TI am getting WRONG output.
Is there any constraints with record length with comm? The above files are the two consective ... (2 Replies)
Hello,
I am practising awk and decided to compare two columns and print the result of the comparison as third column
i/p data
c1,c2,c3
1,a,b
1,b,b
i am trying to compare the last two columns and if they match I am trying to print match else mismatch(Ideally i want that as a last column... (5 Replies)
Discussion started by: mkathi
5 Replies
LEARN ABOUT OSF1
regcmp
regcmp(3) Library Functions Manual regcmp(3)NAME
regcmp, regex - Compile and execute regular expression
LIBRARY
Standard C Library (libc.so, libc. a)
SYNOPSIS
#include <libgen.h>
char *regcmp( const char *string1, ... /*, (char *)0 */);
char *regex( const char *re, const char *subject, ... );
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
regcmp(), regex(): XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
PARAMETERS
Points to the string that is to be matched or converted. Points to a compiled regular expression string. Points to the string that is to
be matched against re.
DESCRIPTION
The regcmp() function compiles a regular expression consisting of the concatenated arguments and returns a pointer to the compiled form.
The end of arguments is indicated by a null pointer. The malloc() function is used to create space for the compiled form. It is the
responsibility of the process to free unneeded space so allocated. A null pointer returned from regcmp() indicates an invalid argument.
The regex() function executes a compiled pattern against the subject string. Additional arguments of type char must be passed to receive
matched subexpressions back. A global character pointer, __loc1, points to the first matched character in the subject string.
The regcmp() and regex() functions support the simple regular expressions which are defined in the grep(1) reference page, but the syntax
and semantics are slightly different. The following are the valid symbols and their associated meanings: The left and right bracket,
asterisk, period, and circumflex symbols retain their meanings as defined in the grep(1) reference page. A dollar sign matches the end of
the string;
matches a new line. Used within brackets, the hyphen signifies an ASCII character range. For example [a-z] is equivalent
to [abcd...xyz]. The - (hyphen) can represent itself only if used as the first or last character. For example, the character class
expression []-] matches the characters ] (right bracket) and - (hyphen). A regular expression followed by a + (plus sign) means one or
more times. For example, [0-9]+ is equivalent to [0-9][0-9]*. Integer values enclosed in {} braces indicate the number of times the pre-
ceding regular expression can be applied. The value m is the minimum number and u is a number, less than 256, which is the maximum. The
syntax {m} indicates the exact number of times the regular expression can be applied. The syntax {m,} is analogous to {m,infinity}. The +
(plus sign) and * (asterisk) operations are equivalent to {1,} and {0,}, respectively. The value of the enclosed regular expression is
returned. The value is stored in the (n+1)th argument following the subject argument. A maximum of ten enclosed regular expressions are
allowed. The regex() function makes its assignments unconditionally. Parentheses are used for grouping. An operator, such as *, +, or
{}, can work on a single character or a regular expression enclosed in parentheses. For example, (a*(cb+)*)$0.
Since all of the symbols defined above are special characters, they must be escaped to be used as themselves.
NOTES
The regcmp() and regex() interfaces are scheduled to be withdrawn from a future version of the X/Open CAE Specification.
These interfaces are obsolete; they are guaranteed to function properly only in the C/POSIX locale and so should be avoided. Use the POSIX
regcomp() interface instead of regcmp() and regex().
RETURN VALUES
Upon successful completion, the regcmp() function returns a pointer to the compiled regular expression. Otherwise, a null pointer is
returned and errno may be set to indicate the error.
Upon successful completion, the regex() function returns a pointer to the next unmatched character in the subject string. Otherwise, a
null pointer is returned.
RELATED INFORMATION
Commands: grep(1)
Functions: malloc(3), regcomp(3)
Standards: standards(5) delim off
regcmp(3)