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Full Discussion: grep to get line numbers
Top Forums UNIX for Dummies Questions & Answers grep to get line numbers Post 302514086 by Corona688 on Thursday 14th of April 2011 07:12:21 PM
Old 04-14-2011
grep does one thing: match lines. It's not a language, so it can't match things conditionally.

awk is a language though, with features that let you build small scripts that do a lot.

It seems cryptic but there's a simple secret to understanding it: The code inside the single big { } block is run repeatedly, once every single line, and sets variables $0(entire line), $1 (first token), $2, ... $NR as it splits the line apart on spaces. The difference between N and $N, is that N gives you the contents of the variable N, and $N gives you the contents of token number N(if N was 4, you get token 4)

Code:
# Print with line numbers.
# It sets the entire line, $0, to the special var NR (line number),
# followed by :, followed by the rest of the original line.
# The 1 at the end is a statement telling it whether to print or not.
# 1 is always true, so always prints.
awk '{ $0=NR ":" $0; } 1' inputfile

# /one/ is only true when the input string contains one, so
# this numbers the lines but only prints lines containing 'one'.
awk '{ $0=NR ":" $0; } /one/' inputfile

# The same as above, with another condition, odd lines only
awk '{ $0=NR ":" $0; } /one/ && (NR%2)' inputfile

# Same as above except even lines only
awk '{ $0=NR ":" $0; } /one/ && !(NR%2)' inputfile

 

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LEARN ABOUT OPENSOLARIS

fmt

fmt(1)								   User Commands							    fmt(1)

NAME

       fmt - simple text formatters

SYNOPSIS

       fmt [-cs] [-w width | -width] [inputfile]...

DESCRIPTION

       fmt  is a simple text formatter that fills and joins lines  to produce output lines of (up to) the number of characters specified in the -w
       width option. The default  width is 72. fmt concatenates the inputfiles listed as arguments. If none are given, fmt formats text  from  the
       standard input.

       Blank lines are preserved in the output, as is the spacing between words. fmt does not fill nor split lines beginning with a `.' (dot), for
       compatibility with nroff(1). Nor does it fill or split a set of contiguous non-blank lines which is determined to be  a	mail  header,  the
       first line of which must begin with "From".

       Indentation is preserved in the output, and input lines with differing indentation are not joined (unless -c is used).

       fmt can also be used as an in-line text filter for vi(1). The  vi command:

       !}fmt

       reformats the text between the cursor location and the end of the paragraph.

OPTIONS

       -c		    Crown  margin  mode.  Preserve the indentation of the first two lines within a paragraph, and align the left margin of
			    each subsequent line with that of the second line. This is useful for tagged paragraphs.

       -s		    Split lines only. Do not join short lines to form longer ones. This prevents sample lines of code, and other such for-
			    matted text, from being unduly combined.

       -w width | -width    Fill output lines to up to	width columns.

OPERANDS

       inputfile    Input file.

ENVIRONMENT VARIABLES

       See environ(5) for a description of the LC_CTYPE environment variable that affects the execution of fmt.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       nroff(1), vi(1), attributes(5), environ(5)

NOTES

       The -width option is acceptable for BSD compatibility, but it may go away in future releases.

SunOS 5.11							    9 May 1997								    fmt(1)
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