System/OneLiner - Revision history

Eadam: /* SELECTIVE DELETION OF CERTAIN LINES */

2012-09-15T11:54:18Z

SELECTIVE DELETION OF CERTAIN LINES

Eadam at 11:53, 15 September 2012

2012-09-15T11:53:20Z

Eadam at 11:50, 15 September 2012

2012-09-15T11:50:56Z

Eadam: /* double space a file */

2012-09-15T11:49:15Z

double space a file

Eadam: /* NUMBERING */

2012-09-15T11:48:55Z

NUMBERING

Eadam at 11:48, 15 September 2012

2012-09-15T11:48:22Z

Eadam at 11:46, 15 September 2012

2012-09-15T11:46:55Z

Eadam at 11:46, 15 September 2012

2012-09-15T11:46:47Z

Eadam at 11:46, 15 September 2012

2012-09-15T11:46:34Z

Eadam: Created page with "HANDY ONE-LINERS FOR SED (Unix stream editor) Oct. 29, 1997 Taken from Compiled by Eric Pement ver..."

2012-09-15T11:46:09Z

Created page with "HANDY ONE-LINERS FOR SED (Unix stream editor) Oct. 29, 1997 Taken from <http://www.unixguide.net/unix/sedoneliner.shtml> Compiled by Eric Pement <epement@jpusa.chi.il.us> ver..."

New page

HANDY ONE-LINERS FOR SED (Unix stream editor) Oct. 29, 1997
Taken from <http://www.unixguide.net/unix/sedoneliner.shtml>
Compiled by Eric Pement <epement@jpusa.chi.il.us> version 4.3
Latest version of this file is always at <http://www.wollery.demon.co.uk>
FILE SPACING:

# double space a file
sed G

# triple space a file
sed 'G;G'

# undo double-spacing (assumes even-numbered lines are always blank)
sed 'n;d'

NUMBERING:

# number each line of a file (simple left alignment). Using a tab (see
# note on '\t' at end of file) instead of space will preserve margins.
sed = filename | sed 'N;s/\n/\t/'

# number each line of a file (number on left, right-aligned)
sed = filename | sed 'N; s/^/ /; s/ *$.\{6,\}$\n/\1 /'

# number each line of file, but only print numbers if line is not blank
sed '/./=' filename | sed '/./N; s/\n/ /'

# count lines (emulates "wc -l")
sed -n '$='

TEXT CONVERSION AND SUBSTITUTION:

# IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format
sed 's/.$//'

# IN DOS ENVIRONMENT: convert Unix newlines (LF) to DOS format
sed 's/$//' # method 1
sed -n p # method 2

# delete leading whitespace (spaces, tabs) from front of each line
# aligns all text flush left
sed 's/^[ \t]*//' # see note on '\t' at end of file

# delete trailing whitespace (spaces, tabs) from end of each line
sed 's/[ \t]*$//' # see note on '\t' at end of file

# delete BOTH leading and trailing whitespace from each line
sed 's/^[ \t]*//;s/[ \t]*$//'

# insert 5 blank spaces at beginning of each line (make page offset)
sed 's/^/ /'

# align all text flush right on a 79-column width
sed -e :a -e 's/^.\{1,78\}$/ &/;ta' # set at 78 plus 1 space

# center all text in the middle of 79-column width. In method 1,
# spaces at the beginning of the line are significant, and trailing
# spaces are appended at the end of the line. In method 2, spaces at
# the beginning of the line are discarded in centering the line, and
# no trailing spaces appear at the end of lines.
sed -e :a -e 's/^.\{1,77\}$/ & /;ta' # method 1
sed -e :a -e 's/^.\{1,77\}$/ &/;ta' -e 's/$ *$\1/\1/' # method 2

# substitute (find & replace) "foo" with "bar" on each line
sed 's/foo/bar/' # replaces only 1st instance in a line
sed 's/foo/bar/4' # replaces only 4th instance in a line
sed 's/foo/bar/g' # replaces ALL instances in a line

# substitute "foo" with "bar" ONLY for lines which contain "baz"
sed '/baz/s/foo/bar/g'

# substitute "foo" with "bar" EXCEPT for lines which contain "baz"
sed '/baz/!s/foo/bar/g'

# reverse order of lines (emulates "tac")
sed '1!G;h;$!d'

# reverse each character on the line (emulates "rev")
sed '/\n/!G;s/$.$$.*\n$/&\2\1/;//D;s/.//'

# join pairs of lines side-by-side (like "paste")
sed 'N;s/\n/ /'

SELECTIVE PRINTING OF CERTAIN LINES:

# print first 10 lines of file (emulates behavior of "head")
sed 10q

# print first line of file (emulates "head -1")
sed q

# print last 10 lines of file (emulates "tail")
sed -e :a -e '$q;N;11,$D;ba'

# print last line of file (emulates "tail -1")
sed '$!d'

# print only lines which match regular expression (emulates "grep")
sed -n '/regexp/p' # method 1
sed '/regexp/!d' # method 2

# print only lines which do NOT match regexp (emulates "grep -v")
sed -n '/regexp/!p' # method 1, corresponds to above
sed '/regexp/d' # method 2, simpler syntax

# print 1 line of context before and after regexp, with line number
# indicating where the regexp occurred (similar to "grep -A1 -B1")
sed -n -e '/regexp/{=;x;1!p;g;$!N;p;D;}' -e h

# grep for AAA and BBB and CCC (in any order)
sed '/AAA/!d; /BBB/!d; /CCC/!d'

# grep for AAA or BBB or CCC (emulates "egrep")
sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d

# print only lines of 65 characters or longer
sed -n '/^.\{65\}/p'

# print only lines of less than 65 characters
sed -n '/^.\{65\}/!p' # method 1, corresponds to above
sed '/^.\{65\}/d' # method 2, simpler syntax

# print section of file from regular expression to end of file
sed -n '/regexp/,$p'

# print section of file based on line numbers (lines 8-12, inclusive)
sed -n '8,12p' # method 1
sed '8,12!d' # method 2

# print line number 52
sed -n '52p' # method 1
sed '52!d' # method 2
sed '52q;d' # method 3, efficient on large files

# print section of file between two regular expressions (inclusive)
sed -n '/Iowa/,/Montana/p' # case sensitive

SELECTIVE DELETION OF CERTAIN LINES:

# print all of file EXCEPT section between 2 regular expressions
sed '/Iowa/,/Montana/d'

# delete duplicate lines from a sorted file (emulates "uniq"). First
# line in a set of duplicate lines is kept, the rest are deleted
sed '$!N; /^$.*$\n\1$/!P; D'

# delete ALL blank lines from a file (same as "grep '.' ")
sed '/^$/d'

# delete all CONSECUTIVE blank lines from file except the first; also
# deletes all blank lines from top and end of file (emulates "cat -s")
sed '/./,/^$/!d' # method 1, allows 0 blanks at top, 1 at EOF
sed '/^$/N;/\n$/D' # method 2, allows 1 blank at top, 0 at EOF

# delete all CONSECUTIVE blank lines from file except the first 2:
sed '/^$/N;/\n$/N;//D'

# delete all leading blank lines at top of file
sed '/./,$!d'

# delete all trailing blank lines at end of file
sed -e :a -e '/^\n*$/N;/\n$/ba'

SPECIAL APPLICATIONS:

# remove nroff overstrikes (char, backspace) from man pages
sed "s/.`echo \\\b`//g" # double quotes required for Unix environment
sed 's/.\x08//g' # hex expression for GNU sed (octal is "\010")

# get Usenet/e-mail message header
sed '/^$/q' # deletes everything after first blank line

# get Usenet/e-mail message body
sed '1,/^$/d' # deletes everything up to first blank line

# get Subject header, but remove initial "Subject: " portion
sed '/^Subject: */!d; s///;q'

# get return address header
sed '/^Reply-To:/q; /^From:/h; /./d;g;q'

# parse out the address proper. Pulls out the e-mail address by itself
# from the 1-line return address header (see preceding script)
sed 's/ *(.*)//; s/>.*//; s/.*[:<] *//'

# add a leading angle bracket and space to each line (quote a message)
sed 's/^/> /

# delete leading angle bracket & space from each line (unquote a message)
sed 's/^> //'

# remove most HTML tags (accommodates multiple-line tags)
sed -e :a -e 's/<[^<]*>/ /g;/</{N;s/\n/ /;ba;}'

# extract multi-part uuencoded binaries, removing extraneous header
# info, so that only the uuencoded portion remains. Files passed to
# sed must be passed in the proper order. Version 1 can be entered
# from the command line; version 2 can be made into an executable
# Unix shell script. (Modified from a script by Rahul Dhesi.)
sed '/^end/,/^begin/d' file1 file2 ... fileX | uudecode # vers. 1
sed '/^end/,/^begin/d' $* | uudecode # vers. 2

# zip up each .TXT file individually, deleting the source file and
# setting the name of each .ZIP file to the basename of the .TXT file
# (under DOS: the "dir /b" switch returns bare filenames in all caps).
echo @echo off >zipup.bat
dir /b *.txt | sed "s/^$.*$\.TXT/pkzip -mo \1 \1.TXT/" >>zipup.bat

TYPICAL USE: Sed takes one or more editing commands and applies all of
them, in sequence, to each line of input. After all the commands have
been applied to the first input line, that line is output and a second
input line is taken for processing, and the cycle repeats. The
preceding examples assume that input comes from the standard input
device (i.e, the console, normally this will be piped input). One or
more filenames can be appended to the command line if the input does
not come from stdin. Output is sent to stdout (the screen). Thus:

cat filename | sed '10q' # uses piped input
sed '10q' filename # same effect, avoids a useless "cat"
sed '10q' filename > newfile # redirects output to disk

For additional syntax instructions, including the way to apply editing
commands from a disk file instead of the command line, consult "sed &
awk, 2nd Edition," by Dale Dougherty and Arnold Robbins (O'Reilly,
1997; http://www.ora.com), "UNIX Text Processing," by Dale Dougherty
and Tim O'Reilly (Hayden Books, 1987) or the tutorials by Mike Arst
distributed in U-SEDIT2.ZIP (many sites). To fully exploit the power
of sed, one must understand "regular expressions." For this, see
"Mastering Regular Expressions" by Jeffrey Friedl (O'Reilly, 1997).
The manual ("man") pages on Unix systems may be helpful (try "man
sed", "man regexp", or the subsection on regular expressions in "man
ed"), but man pages are notoriously difficult. They are not written to
teach sed use or regexps to first-time users, but as a reference text
for those already acquainted with these tools.

QUOTING SYNTAX: The preceding examples use single quotes ('...')
instead of double quotes ("...") to enclose editing commands, since
sed is typically used on a Unix platform. Single quotes prevent the
Unix shell from intrepreting the dollar sign ($) and backquotes
(`...`), which are expanded by the shell if they are enclosed in
double quotes. Users of the "csh" shell and derivatives will also need
to quote the exclamation mark (!) with the backslash (i.e., \!) to
properly run the examples listed above, even within single quotes.
Versions of sed written for DOS invariably require double quotes
("...") instead of single quotes to enclose editing commands.

USE OF '\t' IN SED SCRIPTS: For clarity in documentation, we have used
the expression '\t' to indicate a tab character (0x09) in the scripts.
However, most versions of sed do not recognize the '\t' abbreviation,
so when typing these scripts from the command line, you should press
the TAB key instead. '\t' is supported as a regular expression
metacharacter in awk, perl, and in a few implementations of sed.

VERSIONS OF SED: Versions of sed do differ, and some slight syntax
variation is to be expected. In particular, most do not support the
use of labels (:name) or branch instructions (b,t) within editing
commands, except at the end of those commands. We have used the syntax
which will be portable to most users of sed, even though the popular
GNU versions of sed allow a more succinct syntax. When the reader sees
a fairly long command such as this:

sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d

it is heartening to know that GNU sed will let you reduce it to:

sed '/AAA/b;/BBB/b;/CCC/b;d'

In addition, remember that while many versions of sed accept a command
like "/one/ s/RE1/RE2/", some do NOT allow "/one/! s/RE1/RE2/", which
contains space before the 's'. Omit the space when typing the command.

OPTIMIZING FOR SPEED: If execution speed needs to be increased (due to
large input files or slow processors or hard disks), substitution will
be executed more quickly if the "find" expression is specified before
giving the "s/.../.../" instruction. Thus:

sed 's/foo/bar/g' filename # standard replace command
sed '/foo/ s/foo/bar/g' filename # executes more quickly
sed '/foo/ s//bar/g' filename # shorthand sed syntax

On line selection or deletion in which you only need to output lines
from the first part of the file, a "quit" command (q) in the script
will drastically reduce processing time for large files. Thus:

sed -n '45,50p' filename # print line nos. 45-50 of a file
sed -n '51q;45,50p' filename # same, but executes much faster

If you have any additional scripts to contribute or if you find errors
in this document, please send e-mail to the compiler. Indicate the
version of sed you used, the operating system it was compiled for, and
the nature of the problem. Various scripts in this file were written
or contributed by:

Al Aab <af137@freenet.toronto.on.ca> # "seders" list moderator
Dale Dougherty <dale@songline.com> # author of "sed & awk"
Carlos Duarte <cdua@algos.inesc.pt> # author of "do it with sed"
Eric Pement <epement@jpusa.chi.il.us> # author of this document
S.G.Ravenhall <S.G.Ravenhall@open.ac.uk> # great de-html script
Greg Ubben <gsu@romulus.ncsc.mil> # many contributions & much help

-------------------------------------------------------------------------

A better script for removing duplicate lines
By : erdizz ( Wed Oct 10 11:57:34 2007 )
Cheers
By : Roy ( Tue Mar 27 05:37:21 2007 )
michael
By : michael ( Sun Oct 29 23:05:13 2006 )
Nike
By : Nike ( Fri Oct 20 00:43:34 2006 )
Bush
By : Bush ( Fri Sep 8 01:53:11 2006 )

@@ Line 6: / Line 6: @@
 ==== double space a file ====
-sed G
+ sed G
 ==== triple space a file ====

@@ Line 16: / Line 16: @@
 === NUMBERING ===
-==== number each line of a file (simple left alignment). Using a tab (see
+==== number each line of a file (simple left alignment). Using a tab (see note on '\t' at end of file) instead of space will preserve margins. ====
 sed = filename | sed 'N;s/\n/\t/'
-# number each line of a file (number on left, right-aligned)
+==== number each line of a file (number on left, right-aligned) ====
 sed = filename | sed 'N; s/^/ /; s/ *\(.\{6,\}\)\n/\1 /'
-# number each line of file, but only print numbers if line is not blank
+==== number each line of file, but only print numbers if line is not blank ====
 sed '/./=' filename | sed '/./N; s/\n/ /'
-# count lines (emulates "wc -l")
+==== count lines (emulates "wc -l") ====
 sed -n '$='

@@ Line 5: / Line 5: @@
 FILE SPACING:
-=== double space a file ===
+==== double space a file ====
 sed G

@@ Line 5: / Line 5: @@
 FILE SPACING:
-=== double space a file
+=== double space a file ===
 sed G

@@ Line 132: / Line 132: @@
 === SELECTIVE DELETION OF CERTAIN LINES ===
-# print all of file EXCEPT section between 2 regular expressions
+==== print all of file EXCEPT section between 2 regular expressions
-sed '/Iowa/,/Montana/d'
+ sed '/Iowa/,/Montana/d'
-# delete duplicate lines from a sorted file (emulates "uniq"). First
+==== delete duplicate lines from a sorted file (emulates "uniq"). First  line in a set of duplicate lines is kept, the rest are deleted ====
-# line in a set of duplicate lines is kept, the rest are deleted
+ sed '$!N; /^\(.*\)\n\1$/!P; D'
-# delete ALL blank lines from a file (same as "grep '.' ")
+==== delete ALL blank lines from a file (same as "grep '.' ") ====
-sed '/^$/d'
+ sed '/^$/d'
-# delete all CONSECUTIVE blank lines from file except the first; also
+==== delete all CONSECUTIVE blank lines from file except the first; also deletes all blank lines from top and end of file (emulates "cat -s") ====
-# deletes all blank lines from top and end of file (emulates "cat -s")
+ sed '/./,/^$/!d' # method 1, allows 0 blanks at top, 1 at EOF
-sed '/./,/^$/!d' # method 1, allows 0 blanks at top, 1 at EOF
+ sed '/^$/N;/\n$/D' # method 2, allows 1 blank at top, 0 at EOF
-# delete all CONSECUTIVE blank lines from file except the first 2:
+==== delete all CONSECUTIVE blank lines from file except the first 2 ====
-sed '/^$/N;/\n$/N;//D'
+ sed '/^$/N;/\n$/N;//D'
-# delete all leading blank lines at top of file
+==== delete all leading blank lines at top of file ====
-sed '/./,$!d'
+ sed '/./,$!d'
-# delete all trailing blank lines at end of file
+==== delete all trailing blank lines at end of file ====
-sed -e :a -e '/^\n*$/N;/\n$/ba'
+ sed -e :a -e '/^\n*$/N;/\n$/ba'
 === SPECIAL APPLICATIONS ===

@@ Line 31: / Line 31: @@
 ==== IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format ====
-sed 's/.$//'
+ sed 's/.$//'
 ==== IN DOS ENVIRONMENT: convert Unix newlines (LF) to DOS format ====
-sed 's/$//' # method 1
+ sed 's/$//' # method 1
-sed -n p # method 2
+ sed -n p # method 2
 ==== delete leading whitespace (spaces, tabs) from front of each line aligns all text flush left ====
-sed 's/^[ \t]*//' # see note on '\t' at end of file
+ sed 's/^[ \t]*//' # see note on '\t' at end of file
 ==== delete trailing whitespace (spaces, tabs) from end of each line ====
-sed 's/[ \t]*$//' # see note on '\t' at end of file
+ sed 's/[ \t]*$//' # see note on '\t' at end of file
 ==== delete BOTH leading and trailing whitespace from each line ====
-sed 's/^[ \t]*//;s/[ \t]*$//'
+ sed 's/^[ \t]*//;s/[ \t]*$//'
 ==== insert 5 blank spaces at beginning of each line (make page offset) ====
-sed 's/^/ /'
+ sed 's/^/ /'
 ==== align all text flush right on a 79-column width ====
-sed -e :a -e 's/^.\{1,78\}$/ &/;ta' # set at 78 plus 1 space
+ sed -e :a -e 's/^.\{1,78\}$/ &/;ta' # set at 78 plus 1 space
 ==== center all text in the middle of 79-column width.====
 In method 1, spaces at the beginning of the line are significant, and trailing spaces are appended at the end of the line. In method 2, spaces at the beginning of the line are discarded in centering the line, and no trailing spaces appear at the end of lines.
-sed -e :a -e 's/^.\{1,77\}$/ & /;ta' # method 1
+ sed -e :a -e 's/^.\{1,77\}$/ & /;ta' # method 1
-sed -e :a -e 's/^.\{1,77\}$/ &/;ta' -e 's/\( *\)\1/\1/' # method 2
+ sed -e :a -e 's/^.\{1,77\}$/ &/;ta' -e 's/\( *\)\1/\1/' # method 2
 ==== substitute (find & replace) "foo" with "bar" on each line ====
-sed 's/foo/bar/' # replaces only 1st instance in a line
+ sed 's/foo/bar/' # replaces only 1st instance in a line
-sed 's/foo/bar/4' # replaces only 4th instance in a line
+ sed 's/foo/bar/4' # replaces only 4th instance in a line
-sed 's/foo/bar/g' # replaces ALL instances in a line
+ sed 's/foo/bar/g' # replaces ALL instances in a line
 ==== substitute "foo" with "bar" ONLY for lines which contain "baz" ====
-sed '/baz/s/foo/bar/g'
+ sed '/baz/s/foo/bar/g'
 ==== substitute "foo" with "bar" EXCEPT for lines which contain "baz" ====
-sed '/baz/!s/foo/bar/g'
+ sed '/baz/!s/foo/bar/g'
 ==== reverse order of lines (emulates "tac") ====
-sed '1!G;h;$!d'
+ sed '1!G;h;$!d'
 ==== reverse each character on the line (emulates "rev") ====
-sed '/\n/!G;s/\(.\)\(.*\n\)/&\2\1/;//D;s/.//'
+ sed '/\n/!G;s/\(.\)\(.*\n\)/&\2\1/;//D;s/.//'
 ==== join pairs of lines side-by-side (like "paste") ====
-sed 'N;s/\n/ /'
+ sed 'N;s/\n/ /'
 === SELECTIVE PRINTING OF CERTAIN LINES ===
-# print first 10 lines of file (emulates behavior of "head")
+==== print first 10 lines of file (emulates behavior of "head") ====
-sed 10q
+ sed 10q
-# print first line of file (emulates "head -1")
+==== print first line of file (emulates "head -1") ====
-sed q
+ sed q
-# print last 10 lines of file (emulates "tail")
+==== print last 10 lines of file (emulates "tail") ====
-sed -e :a -e '$q;N;11,$D;ba'
+ sed -e :a -e '$q;N;11,$D;ba'
-# print last line of file (emulates "tail -1")
+==== print last line of file (emulates "tail -1") ====
-sed '$!d'
+ sed '$!d'
-# print only lines which match regular expression (emulates "grep")
+==== print only lines which match regular expression (emulates "grep") ====
-sed -n '/regexp/p' # method 1
+ sed -n '/regexp/p' # method 1
-sed '/regexp/!d' # method 2
+ sed '/regexp/!d' # method 2
-# print only lines which do NOT match regexp (emulates "grep -v")
+==== print only lines which do NOT match regexp (emulates "grep -v") ====
-sed -n '/regexp/!p' # method 1, corresponds to above
+ sed -n '/regexp/!p' # method 1, corresponds to above
-sed '/regexp/d' # method 2, simpler syntax
+ sed '/regexp/d' # method 2, simpler syntax
-# print 1 line of context before and after regexp, with line number
+==== print 1 line of context before and after regexp, with line number indicating where the regexp occurred (similar to "grep -A1 -B1") ====
-# indicating where the regexp occurred (similar to "grep -A1 -B1")
+ sed -n -e '/regexp/{=;x;1!p;g;$!N;p;D;}' -e h
-# grep for AAA and BBB and CCC (in any order)
+==== grep for AAA and BBB and CCC (in any order) ====
-sed '/AAA/!d; /BBB/!d; /CCC/!d'
+ sed '/AAA/!d; /BBB/!d; /CCC/!d'
-# grep for AAA or BBB or CCC (emulates "egrep")
+==== grep for AAA or BBB or CCC (emulates "egrep") ====
-sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d
+ sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d
-# print only lines of 65 characters or longer
+==== print only lines of 65 characters or longer ====
-sed -n '/^.\{65\}/p'
+ sed -n '/^.\{65\}/p'
-# print only lines of less than 65 characters
+==== print only lines of less than 65 characters ====
-sed -n '/^.\{65\}/!p' # method 1, corresponds to above
+ sed -n '/^.\{65\}/!p' # method 1, corresponds to above
-sed '/^.\{65\}/d' # method 2, simpler syntax
+ sed '/^.\{65\}/d' # method 2, simpler syntax
-# print section of file from regular expression to end of file
+==== print section of file from regular expression to end of file ====
-sed -n '/regexp/,$p'
+ sed -n '/regexp/,$p'
-# print section of file based on line numbers (lines 8-12, inclusive)
+==== print section of file based on line numbers (lines 8-12, inclusive) ====
-sed -n '8,12p' # method 1
+ sed -n '8,12p' # method 1
-sed '8,12!d' # method 2
+ sed '8,12!d' # method 2
-# print line number 52
+==== print line number 52 ====
-sed -n '52p' # method 1
+ sed -n '52p' # method 1
-sed '52!d' # method 2
+ sed '52!d' # method 2
-sed '52q;d' # method 3, efficient on large files
+ sed '52q;d' # method 3, efficient on large files
-# print section of file between two regular expressions (inclusive)
+==== print section of file between two regular expressions (inclusive) ====
-sed -n '/Iowa/,/Montana/p' # case sensitive
+ sed -n '/Iowa/,/Montana/p' # case sensitive
 === SELECTIVE DELETION OF CERTAIN LINES ===

@@ Line 8: / Line 8: @@
 sed G
-# triple space a file
+==== triple space a file ====
 sed 'G;G'
-# undo double-spacing (assumes even-numbered lines are always blank)
+==== undo double-spacing (assumes even-numbered lines are always blank) ====
 sed 'n;d'
-NUMBERING:
+=== NUMBERING ===
-# number each line of a file (simple left alignment). Using a tab (see
+==== number each line of a file (simple left alignment). Using a tab (see
-# note on '\t' at end of file) instead of space will preserve margins.
+# note on '\t' at end of file) instead of space will preserve margins. ====
 sed = filename | sed 'N;s/\n/\t/'
@@ Line 29: / Line 29: @@
 sed -n '$='
-TEXT CONVERSION AND SUBSTITUTION:
+=== TEXT CONVERSION AND SUBSTITUTION ===
 # IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format
@@ Line 82: / Line 82: @@
 sed 'N;s/\n/ /'
-SELECTIVE PRINTING OF CERTAIN LINES:
+=== SELECTIVE PRINTING OF CERTAIN LINES ===
 # print first 10 lines of file (emulates behavior of "head")
@@ Line 136: / Line 136: @@
 sed -n '/Iowa/,/Montana/p' # case sensitive
-SELECTIVE DELETION OF CERTAIN LINES:
+=== SELECTIVE DELETION OF CERTAIN LINES ===
 # print all of file EXCEPT section between 2 regular expressions
@@ Line 162: / Line 162: @@
 sed -e :a -e '/^\n*$/N;/\n$/ba'
-SPECIAL APPLICATIONS:
+=== SPECIAL APPLICATIONS ===
 # remove nroff overstrikes (char, backspace) from man pages