Regular expressions, as such, only "match", they don't "extract". Some scripting languages have a facility for returning the part of a regular expression which matched, but it then depends on which language you want.
Without more information about what to look for precisely, the simple answer is that the regular expression "y" will match the letter "y", and the matching (extracted) string will always be "y".
If you want the first substring between two periods, that's something like this:
or with Perl:
or with awk:
The latter doesn't use regular expressions at all, though.
But really, you need to explain in more detail what the parameters of the problem are.
Last edited by era; 05-29-2008 at 04:30 AM..
Reason: Add Perl example
Hi Friends,
Can any of you explain me about the below line of code?
mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'`
Im not able to understand, what exactly it is doing :confused:
Any help would be useful for me.
Lokesha (4 Replies)
I have 2000 files named like "file-fr0000.log", "file-fr1999.log"...
I wanna generate the file names automatically in the following c shell script:
set fr = 0
while ($fr <= 1999)
grep "ENERGY" file-fr$fr.log > data.dat
@ fr = ( $fr + 1 )
end
The above will generate file names... (3 Replies)
hello,
I am writting a regular expression that intend to match any tunnel or serial interface but it doesn't mtach any serial sub-interface.
For example, statement should match "Tunnel3" or "Serial0/1" but shouldn't match "Serial0\1.1" (doesn't include dot ".")
I tried the following but... (3 Replies)
Hi,
I have line in input file as below:
3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL
My expected output for line in the file must be :
"1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL"
Can someone... (7 Replies)
How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address
and column 3 contains “cc” e-mail address to include with same email.
Sample input file, email.txt
Below is an sample code where... (2 Replies)
Hi All,
I have 2 pipe delimited files viz., file_old and file_new. I'm trying to compare these 2 files, and extract all the different rows between them into a new_file.
comm -3 < sort file_old < sort file_new > new_file
I am getting the below error:
-ksh: sort: cannot open
But if I do... (7 Replies)
Hello.
System : opensuse leap 42.3
I have a bash script that build a text file.
I would like the last command doing :
print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt
where :
print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies
LEARN ABOUT PLAN9
regexp
REGEXP(6) Games Manual REGEXP(6)NAME
regexp - regular expression notation
DESCRIPTION
A regular expression specifies a set of strings of characters. A member of this set of strings is said to be matched by the regular
expression. In many applications a delimiter character, commonly bounds a regular expression. In the following specification for regular
expressions the word `character' means any character (rune) but newline.
The syntax for a regular expression e0 is
e3: literal | charclass | '.' | '^' | '$' | '(' e0 ')'
e2: e3
| e2 REP
REP: '*' | '+' | '?'
e1: e2
| e1 e2
e0: e1
| e0 '|' e1
A literal is any non-metacharacter, or a metacharacter (one of .*+?[]()|^$), or the delimiter preceded by
A charclass is a nonempty string s bracketed [s] (or [^s]); it matches any character in (or not in) s. A negated character class never
matches newline. A substring a-b, with a and b in ascending order, stands for the inclusive range of characters between a and b. In s,
the metacharacters an initial and the regular expression delimiter must be preceded by a other metacharacters have no special meaning and
may appear unescaped.
A matches any character.
A matches the beginning of a line; matches the end of the line.
The REP operators match zero or more (*), one or more (+), zero or one (?), instances respectively of the preceding regular expression e2.
A concatenated regular expression, e1e2, matches a match to e1 followed by a match to e2.
An alternative regular expression, e0|e1, matches either a match to e0 or a match to e1.
A match to any part of a regular expression extends as far as possible without preventing a match to the remainder of the regular expres-
sion.
SEE ALSO awk(1), ed(1), sam(1), sed(1), regexp(2)REGEXP(6)