perl: reg.expr: combine starting and ending removal in one exprecion
Hello,
I am new in perl and in regular exprecion; so I am looking for help (or an experienced advise.)
The target is a triming spaces from a string: i.e., remove spases from begining and from end of a string.
One of main point of a searched solution is performance: for current task it is very important.
Therefore simple loop character by character seems to me ineffective.
I guess the reg.exp. engine should be pretty sufficient.
So, I've come out with:
This works fine,but,
first of all: I could not combine both patern into one exprecion.
Would you suggest how it could be done?
second: What about time? What expected to be longer : one more complicated regexp or twice, but simple? Who know how that task is processed inside of perl?
And last question: is there simpler way to do such simple task in perl?
In a shell script, how I can achieve substitution of shell script var to a regular
expression, as shown below.
var=`head -1 file1`
awk '$0!~/$var/ {print $0}' file1 > file2
In the case above $var value literally considered for non-exists criteria. (3 Replies)
Hello!
I've got txt-file containing lots of data in sentences like this:
;;BA;00:00:03:00;COM;CLOQUET-LAFOLLYE;SIMON;
but sometime more than on in a line like this:
;;BA;00:00:03:00;COM;CLOQUET-LAFOLLYE;SIMON;;;BA;00:00:03:00;REA;RTL9;;;;BAC;:00;TIT;SEMAINE SPECIALE ~SSLOGAN~T DVD;;
... (3 Replies)
Hi there!
I'm trying to validate a simple 6 digits number with reg expr. I ONLY want 6 digits so when i type 7 digits the script should no validate the number.
I've write this code:
#!/usr/bin/perl
while(<STDIN>){
if($_=~/\d{6}/){
print "Bingo!\n";
... (2 Replies)
Hi all,
I want to cut a column which match the regular expression "beta", if I don't know the column number?
cat test
alpha;beta;gamma
11;22;33
44;55;66
77;88;99
should be
command ....
beta
22
55 (6 Replies)
Hi All,
I need your input on how to mask out / ignore a string that does not match a working regular expression (continually refining) pattern in Java. Below is the code snippet which is picking up all the lines with the correct regular expression string except one known so far:
public... (0 Replies)
I am trying to check if files staring with filename but ending with diffent dates e.g. filename.2011-10-25.
The code I am using is below
if
It works find only if one file is present but returns binary operator expected
when there are mulptiple files.
Please help me correcting it. I... (5 Replies)
Hi all,
I need to do scrip for printing starting and ending numbers along with count in given file.:wall:
Input: a.txt
10000030
10000029
10000028
10000027
10000026
10000024
10000023
10000021
10000018
10000018
10000017
10000016
10000015
10000014 (2 Replies)
Hello,
Here is my text data excerpted from the webpage:
input
My target is to get:
What i tried is:
sed 's/.*\(connector\)/1/' input > output
but all characters coming before the word "connector" are deleted which is not good for me.
My question: (9 Replies)
im trying to search for a WORD in a file which
begins with a number
followed by a hypen
follwed multiple words
and end with a dot "."
and pront the entire line which matches the above.
Please note that there is a space at the begining of each line
i/p file
19458 00000-CONTROL-PARA.... (5 Replies)
Discussion started by: anijan
5 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