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Top Forums UNIX for Dummies Questions & Answers Need help in Regular Expression Post 302090580 by anbu23 on Tuesday 26th of September 2006 02:06:12 PM
Old 09-26-2006
Code:
awk -v var="^[0-9]" ' $0 ~ var { sub( /:.*$/,"",$0); print }' file

== is for matching exact string
~ is for matching regular expression

or

Code:
sed -n "s/^\([0-9][^:]*\):.*/\1/p" ff

 

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PG(1)								   User Commands							     PG(1)

NAME
pg - browse pagewise through text files SYNOPSIS
pg [-number] [-p string] [-cefnrs] [+line] [+/pattern/] [file...] DESCRIPTION
Pg displays a text file on a CRT one screenful at once. After each page, a prompt is displayed. The user may then either press the newline key to view the next page or one of the keys described below. If no filename is given on the command line, pg reads from standard input. If the standard output is not a terminal, pg acts like cat(1) but precedes each file with its name if there is more than one. If input comes from a pipe, pg stores the data in a buffer file while reading to make navigation possible. OPTIONS
Pg accepts the following options: -number The number of lines per page. Usually, this is the number of CRT lines minus one. -c Clear the screen before a page is displayed if the terminfo entry for the terminal provides this capability. -e pg will not pause and display (EOF) at the end of a file. -f pg does not split long lines. -n Without this option, commands must be terminated by a newline character. With this option, pg advances once a command letter is entered. -p string Instead of the prompt : , string is displayed. If string contains %d , its first occurrence is replaced by the number of the cur- rent page. -r Disallow the shell escape. -s Print messages in standout mode if the terminfo entry for the terminal provides this capability. +number Start at the given line. +/pattern/ Start at the line containing the Basic Regular Expression pattern given. USAGE
The following commands may be entered at the prompt. Commands preceded by i in this document accept a number as argument, positive or nega- tive. If this argument starts with + or -, it is interpreted relative to the current position in the input file, otherwise relative to the beginning. i<newline> Display the next or the indicated page. id or ^D Display the next halfpage. If i is given, it is always interpreted relative to the current position. il Display the next or the indicated line. if Skip a page forward. i must be a positive number and is always interpreted relative to the current position. iw or iz Behave as <newline> except that i becomes the new page size. . or ^L Redraw the screen. $ Advance to the last line of the input file. i/pattern/ Search forward until the first or the i-th occurrence of the Basic Regular Expression pattern is found. The search starts after the current page and stops at the end of the file. No wrap-around is performed. i must be a positive number. i?pattern? or i^pattern^ Search backward until the first or the i-th occurrence of the Basic Regular Expression pattern is found. The search starts before the current page and stops at the beginning of the file. No wrap-around is performed. i must be a positive number. The search commands accept an added letter. If t is given, the line containing the pattern is displayed at the top of the screen, which is the default. m selects the middle and b the bottom of the screen. The selected position is used in following searches, too. in Advance to the next file or i files forward. ip Reread the previous file or i files backward. s filename Save the current file to the given filename. h Display a command summary. !command Execute command using the shell. q or Q Quit. If the user presses the interrupt or quit key while pg reads from the input file or writes on the terminal, pg will immediately display the prompt. In all other situations these keys will terminate pg. ENVIRONMENT VARIABLES
The following environment variables affect the behaviour of pg: COLUMNS Overrides the system-supplied number of columns if set. LANG, LC_ALL, LC_COLLATE, LC_CTYPE, LC_MESSAGES See locale(7). LINES Overrides the system-supplied number of lines if set. SHELL Used by the ! command. TERM Determines the terminal type. SEE ALSO
cat(1), more(1), sh(1), terminfo(5), locale(7), regex(7), term(7) NOTES
pg expects the terminal tabulators to set on eight positions. Files that include NUL characters cannot be displayed by pg. AVAILABILITY
The pg command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/. Gunnar Ritter 2001-04-25 PG(1)
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