1. grep interprets the pattern as a regular expression. Use the asterisk according to this.
2. In regular expressions the asterisk means match the preceding item zero or more times. In your case the letter "w" was matched zero times.
3. The wild card for any character is a dot. If you want to filter for strings starting with ora_dbw followed by any number of irrelevant characters you can formulate it like this:
Last edited by cero; 06-12-2013 at 07:34 AM..
Reason: Expanded explanation of answer 2. + added quotes to the example...
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 ULTRIX
grep
grep(1) General Commands Manual grep(1)Name
grep, egrep, fgrep - search file for regular expression
Syntax
grep [option...] expression [file...]
egrep [option...] [expression] [file...]
fgrep [option...] [strings] [file]
Description
Commands of the family search the input files (standard input default) for lines matching a pattern. Normally, each line found is copied
to the standard output.
The command patterns are limited regular expressions in the style of which uses a compact nondeterministic algorithm. The command patterns
are full regular expressions. The command uses a fast deterministic algorithm that sometimes needs exponential space. The command pat-
terns are fixed strings. The command is fast and compact.
In all cases the file name is shown if there is more than one input file. Take care when using the characters $ * [ ^ | ( ) and in the
expression because they are also meaningful to the Shell. It is safest to enclose the entire expression argument in single quotes ' '.
The command searches for lines that contain one of the (new line-separated) strings.
The command accepts extended regular expressions. In the following description `character' excludes new line:
A followed by a single character other than new line matches that character.
The character ^ matches the beginning of a line.
The character $ matches the end of a line.
A . (dot) 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 an * (asterisk) matches a sequence of 0 or more matches of the regular expression. A regular
expression followed by a + (plus) matches a sequence of 1 or more matches of the regular expression. A regular expression followed
by a ? (question mark) matches a sequence of 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 new line 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 the following: [], then *+?, then concatenation, then | and new
line.
Options-b Precedes each output line with its block number. This is sometimes useful in locating disk block numbers by context.
-c Produces count of matching lines only.
-e expression
Uses next argument as expression that begins with a minus (-).
-f file Takes regular expression (egrep) or string list (fgrep) from file.
-i Considers upper and lowercase letter identical in making comparisons and only).
-l Lists files with matching lines only once, separated by a new line.
-n Precedes each matching line with its line number.
-s Silent mode and nothing is printed (except error messages). This is useful for checking the error status (see DIAGNOSTICS).
-v Displays all lines that do not match specified expression.
-w Searches for an expression as for a word (as if surrounded by `<' and `>'). For further information, see only.
-x Prints exact lines matched in their entirety only).
Restrictions
Lines are limited to 256 characters; longer lines are truncated.
Diagnostics
Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or inaccessible files.
See Alsoex(1), sed(1), sh(1)grep(1)