10-15-2010
Alternative for wc -l
Hi techies ..
This is my first posting hr ..
Am facing a serious performance problem in counting the number of lines in the file. The input files i get will be in some 10 to 15 Gb of size or even sometimes more ..and I will load it to db
I have used wc -l to confirm whether the loader has loaded entire data ...the couting operaion alone consumes more than 45 to 50 mins ...could someone suggest me any other way to get the count of lines in files ..
pls note I cant use sed due to the coding standards followed here ..so pls excuse ..
Any other swifting workaround would be really helpfull ..and appreciated
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head(1) General Commands Manual head(1)
NAME
head - Displays the beginning of files
SYNOPSIS
Current Syntax
head [-c bytes] [-n lines] [file...]
Obsolescent Syntax
head [-lines] [file...]
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
head: XCU5.0
Refer to the standards(5) reference page for more information about industry standards and associated tags.
OPTIONS
The default count is 10. [Tru64 UNIX] Specifies the number of bytes to display. If the last byte written is not a newline character, a
newline character is appended to the output. Specifies the number of lines to display Works exactly as -n lines. Obsolescent.
OPERANDS
Path name of the input file. If you do not specify a file, head reads standard input.
DESCRIPTION
The head command copies the standard input to standard output, ending output of each file at the specified point.
NOTES
The obsolescent form is subject to withdrawal at any time.
EXIT STATUS
The following exit values are returned: Successful completion. An error occurred.
EXAMPLES
To display the first 5 lines of a file called test, enter: head -n 5 test To display the first ten lines of all files (except those with a
name beginning with a period), enter: head *
ENVIRONMENT VARIABLES
The following environment variables affect the execution of head: Provides a default value for the internationalization variables that are
unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization vari-
ables contain an invalid setting, the utility behaves as if none of the variables had been defined. If set to a non-empty string value,
overrides the values of all the other internationalization variables. Determines the locale for the interpretation of sequences of bytes
of text data as characters (for example, single-byte as opposed to multibyte characters in arguments and input files). Determines the
locale for the format and contents of diagnostic messages written to standard error. Determines the location of message catalogues for the
processing of LC_MESSAGES.
SEE ALSO
Commands: cat(1), more(1), pg(1), sed(1), tail(1)
Standards: standards(5)
head(1)