01-06-2014
awk takes a set of files as arguments, which altogether present a stream of lines to it. Line after line is processed, with the internal FILENAME variable changing if need be (if switching to the next file).
Before any of the lines of the stream is read, ALL of the BEGIN actions are being processed. You can use this to initialize variables, print headers, what have you.
After the last line of the entire stream, possibly consisting of many a file, ALL the END actions will be processed, e.g. for printing totals. That means, you can calculate your count[$2]++ during normal processing, and at the END, print out (in whatever structure) what you have computed so far.
And it looks to me as if that's exactly what that code snippet you presented is doing...
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Why would you need to use this in a script?
Why can't you just use print to print out what you want printed in the begining and print for what you want at the end.
So this:
nawk 'BEGIN {print "this is the first line"}
{print $1 $2 $3}
{print $5 $6}
END {print "this is the last line"}'
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Hi all,
i am new to scripting. i need to write a code to detect begin and end of word that either begins or ends with t,th,d,dh,s,sh
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Hi,
Contents of BBS-list file:
foo
foo
foo
awk '
BEGIN { print "Analysis of \"foo\"" }
/foo/ { ++n }
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Analysis of "foo"
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Hi
I have written a script .The script runs properly if i write sql queries .But if i use PLSQL commands of BEGIN if end if , end ,then on running the script the comamds are getting printed on the prompt .
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Hi All ,
I am newbie to linux shell scripting , below are the contents of my log file ,
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Hi!
I have a strange behaviour from sed and awk, but I'm not sure, if I'm doing something wrong:
I have a list of words, where I want to add the following string at the end of each line:
\;\;\;\;0\;1
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Hi All,
test file
Begin Script Run at Thu Mar 14 09:24:16 PDT 2013
tst_accounts: ws zip: WS_out_20130313.tar.gz dat: test_20130313.dat count: 63574 loaded: xx pre-merge: xx post-merge: xx timestamp: Thu Mar 14 09:30:42 PDT 2013
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I'm new to awk, trying to understand the basics.
I'm trying to reset the counter everytime the program gets a new file to check.
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{
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Hello Friends ,
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* Primary*
Servername Server1
Location R201
Rack 4
*End Primary*
*Secondary*
Server Name Server1
IPAddress 10.24.30.10
Application Apache
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Can Someone please explain why BEGIN and END statement is used inside function? How does that help in scripting?
function fileformatting
{
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LEARN ABOUT REDHAT
pcregrep
PCREGREP(1) General Commands Manual PCREGREP(1)
NAME
pcregrep - a grep with Perl-compatible regular expressions.
SYNOPSIS
pcregrep [-Vcfhilnrsvx] pattern [file] ...
DESCRIPTION
pcregrep searches files for character patterns, in the same way as other grep commands do, but it uses the PCRE regular expression library
to support patterns that are compatible with the regular expressions of Perl 5. See pcre(3) for a full description of syntax and semantics.
If no files are specified, pcregrep reads the standard input. By default, each line that matches the pattern is copied to the standard out-
put, and if there is more than one file, the file name is printed before each line of output. However, there are options that can change
how pcregrep behaves.
Lines are limited to BUFSIZ characters. BUFSIZ is defined in <stdio.h>. The newline character is removed from the end of each line before
it is matched against the pattern.
OPTIONS
-V Write the version number of the PCRE library being used to the standard error stream.
-c Do not print individual lines; instead just print a count of the number of lines that would otherwise have been printed. If sev-
eral files are given, a count is printed for each of them.
-ffilename
Read patterns from the file, one per line, and match all patterns against each line. There is a maximum of 100 patterns. Trailing
white space is removed, and blank lines are ignored. An empty file contains no patterns and therefore matches nothing.
-h Suppress printing of filenames when searching multiple files.
-i Ignore upper/lower case distinctions during comparisons.
-l Instead of printing lines from the files, just print the names of the files containing lines that would have been printed. Each
file name is printed once, on a separate line.
-n Precede each line by its line number in the file.
-r If any file is a directory, recursively scan the files it contains. Without -r a directory is scanned as a normal file.
-s Work silently, that is, display nothing except error messages. The exit status indicates whether any matches were found.
-v Invert the sense of the match, so that lines which do not match the pattern are now the ones that are found.
-x Force the pattern to be anchored (it must start matching at the beginning of the line) and in addition, require it to match the
entire line. This is equivalent to having ^ and $ characters at the start and end of each alternative branch in the regular
expression.
SEE ALSO
pcre(3), Perl 5 documentation
DIAGNOSTICS
Exit status is 0 if any matches were found, 1 if no matches were found, and 2 for syntax errors or inacessible files (even if matches were
found).
AUTHOR
Philip Hazel <ph10@cam.ac.uk>
Last updated: 15 August 2001
Copyright (c) 1997-2001 University of Cambridge.
PCREGREP(1)