grep will always output the whole line, no matter how small the part you actually searched for.
That said, the "memory" you're referring to are called "capturing groups", and can even be nested. If, for example, you take the Perl expression
You'd have "a test." in $1, "a" in $2, and "test." in $3
How can i create a regular expression which can detect a new line charcter followed by a special character say * and replace these both by a string of zero length?
Eg:
Input File san.txt
hello
hi ... (6 Replies)
how to find for a file whose name has all characters in uppercase after 'project'?
I tried this:
find . -name 'project**.pdf'
./projectABC.pdf
./projectABC123.pdf
I want only ./projectABC.pdf
What is the regular expression that correponds to "all characters are capital"?
thanks (8 Replies)
I have a flat file with the following drug names
Nutropin AQ 20mg PEN Cart 2ml
Norditropin Cart 15mg/1.5ml
I have to extract digits that are before mg i.e 20 and 15 ; how to do this using regular expressions
Thanks
ram (1 Reply)
In regular expressions with grep(or egrep), ^ works if we want something in starting of line..but what if we write ^^^ or ^ for pattern matching??..Hope u all r familiar with regular expressions for pattern matching.. (1 Reply)
#!/usr/bin/perl
$word = "one last challenge";
if ( $word =~ /^(\w+).*\s(\w+)$/ )
{
print "$1";
print "\n";
print "$2";
}
The output shows that "$1" is with result one and "$2" is with result challenge. I am confused about how this pattern match expression works step by step. I... (8 Replies)
what elements does " /^/ " match?
I did the test which indicates that it matches single lowercase character like 'a','b' etc. and '1','2' etc.
But I really confused with that. Because, "/^abc/" matches strings like "abcedf" or "abcddddee".
So, what does caret ^ really mean?
Any response... (2 Replies)
I have a file that I'm trying to find all the cases of phone number extensions and deleting them. So input file looks like:
abc
x93825
def
13234
x52673
hello
output looks like:
abc
def
13234
hello
Basically delete lines that have 5 numbers following "x". I tried: x\(4) but it... (7 Replies)
I need to pick a part of string lets stay started with specific character and end with specific character to replace using sed command
the line is like this:my audio book 71-skhdfon1dufgjhgf8.wav'
I want to move the characters beginning with - end before.
I have different files with random... (2 Replies)
Discussion started by: XP_2600
2 Replies
LEARN ABOUT OPENDARWIN
while
while(n) Tcl Built-In Commands while(n)
__________________________________________________________________________________________________________________________________________________NAME
while - Execute script repeatedly as long as a condition is met
SYNOPSIS
while test body
_________________________________________________________________DESCRIPTION
The while command evaluates test as an expression (in the same way that expr evaluates its argument). The value of the expression must a
proper boolean value; if it is a true value then body is executed by passing it to the Tcl interpreter. Once body has been executed then
test is evaluated again, and the process repeats until eventually test evaluates to a false boolean value. Continue commands may be exe-
cuted inside body to terminate the current iteration of the loop, and break commands may be executed inside body to cause immediate termi-
nation of the while command. The while command always returns an empty string.
Note: test should almost always be enclosed in braces. If not, variable substitutions will be made before the while command starts execut-
ing, which means that variable changes made by the loop body will not be considered in the expression. This is likely to result in an
infinite loop. If test is enclosed in braces, variable substitutions are delayed until the expression is evaluated (before each loop iter-
ation), so changes in the variables will be visible. For an example, try the following script with and without the braces around $x<10:
set x 0
while {$x<10} {
puts "x is $x"
incr x
}
SEE ALSO
break(n), continue(n), for(n), foreach(n)
KEYWORDS
boolean value, loop, test, while
Tcl while(n)