Here is an example of how to do what you want to do:
From IEEE Std 1003.1:2008
Quote:
The ':' matching operator shall compare the string resulting from the evaluation of expr1 with the regular expression pattern resulting from the evaluation of expr2. Regular expression syntax shall be that defined in the Base Definitions volume of IEEE Std 1003.1-2001, Section 9.3, Basic Regular Expressions, except that all patterns are anchored to the beginning of the string (that is, only sequences starting at the first character of a string are matched by the regular expression) and, therefore, it is unspecified whether '^' is a special character in that context. Usually, the matching operator shall return a string representing the number of characters matched ( '0' on failure). Alternatively, if the pattern contains at least one regular expression subexpression "[\(...\)]", the string corresponding to "\1" shall be returned.
I am looking for the correct syntax on the expr command in UNIX. I have a script that I am building at the moment. the script is creating file1 that is an actual .sql file that is going inside the oracle database to get some information in there. It take that information, puts it inside another... (2 Replies)
Hi, Can anyone please let me know, how to extract two lines at the same time. In specific,I have a file containing list of devices, such as router1 and switch2 below. I want to get all the lines which has "#" and all the lines which has "down"
router1#sh ip int br
Interface ... (6 Replies)
Hi
Can anyone explain me the usage of this command and the arguments used here and what will be the expected output :
v_num=`expr nav_d_20100204_1759 : '*\(*\)'`
what will be the value returned in v_num.
Thanks in Advance!!!
Regards
Naveen Purbia (3 Replies)
Dear Folks,
I am a newbee to UNIX. I want to extract the SQLSTATE from a log file. For example the log file content is
SQL0010N The string constant beginning with "' from table1 a, table 2" does not have
an ending string delimiter. SQLSTATE=42603
when I give the the command as ... (4 Replies)
Hi there, Unix Gurus
Working with big listings of english sentences for my pupils, of the type:
1. If the boss's son had been , someone would have asked for money by now.
2. Look, I haven't a crime, so why can't you let me go?
....
I wondered how to extract the words between brackets in... (7 Replies)
I'm trying to check if a variable'd string is only one character and use that in an if statement the only way I could find is:
$expr "${var}" : . # expr STRING : regrep
where the "." is the grep wildcard for any single character.
Whats wrong with my code here and is there a... (3 Replies)
Hello,
Currently, I have this output from my application :
-------------------------------------------------
Log viewer/Tmp1 (Jun 29 2011 09:48)
-------------------------------------------------
BlalbalbaBlalbalba..Blalbalba..Blalbalba..Blalbalba..Blalbalba..Blalbalba..Blalbalba....... (3 Replies)
I have a sample text file with file name: sample.txt
The text file has the following text.
this is an example text where we have to extract certain words before and after certain word these words can be used later to get more information
I want to extract n (a constant) words before and... (2 Replies)
Hi there, Unixers
I need to extract ALL the words from a text which aresurrounded by square brackets. I am using this piece of code
sed 's/.*\.*/\1/g' inputfile > outputfile
but I only get one word for every paragraph, why?
Please use CODE tags as required by forum rules! (7 Replies)
Discussion started by: eldeingles
7 Replies
LEARN ABOUT OPENDARWIN
expr
EXPR(1) BSD General Commands Manual EXPR(1)NAME
expr -- evaluate expression
SYNOPSIS
expr expression
DESCRIPTION
The expr utility evaluates expression and writes the result on standard output.
All operators are separate arguments to the expr utility. Characters special to the command interpreter must be escaped.
Operators are listed below in order of increasing precedence. Operators with equal precedence are grouped within { } symbols.
expr1 | expr2
Returns the evaluation of expr1 if it is neither an empty string nor zero; otherwise, returns the evaluation of expr2.
expr1 & expr2
Returns the evaluation of expr1 if neither expression evaluates to an empty string or zero; otherwise, returns zero.
expr1 {=, >, >=, <, <=, !=} expr2
Returns the results of integer comparison if both arguments are integers; otherwise, returns the results of string comparison using
the locale-specific collation sequence. The result of each comparison is 1 if the specified relation is true, or 0 if the relation
is false.
expr1 {+, -} expr2
Returns the results of addition or subtraction of integer-valued arguments.
expr1 {*, /, %} expr2
Returns the results of multiplication, integer division, or remainder of integer-valued arguments.
expr1 : expr2
The ``:'' operator matches expr1 against expr2, which must be a regular expression. The regular expression is anchored to the begin-
ning of the string with an implicit ``^''. expr expects "basic" regular expressions, see re_format(7) for more information on regu-
lar expressions.
If the match succeeds and the pattern contains at least one regular expression subexpression ``(...)'', the string corresponding to
``1'' is returned; otherwise the matching operator returns the number of characters matched. If the match fails and the pattern
contains a regular expression subexpression the null string is returned; otherwise 0.
Parentheses are used for grouping in the usual manner.
EXAMPLES
1. The following example adds one to the variable a.
a=`expr $a + 1`
2. The following example returns the filename portion of a pathname stored in variable a. The // characters act to eliminate ambiguity
with the division operator.
expr //$a : '.*/(.*)'
3. The following example returns the number of characters in variable a.
expr $a : '.*'
DIAGNOSTICS
The expr utility exits with one of the following values:
0 the expression is neither an empty string nor 0.
1 the expression is an empty string or 0.
2 the expression is invalid.
STANDARDS
The expr utility conforms to IEEE Std 1003.2 (``POSIX.2'').
BSD July 3, 1993 BSD