cheat sheets.

--- sed version 2	Thu Feb 15 02:31:35 +0000 2007
+++ sed version 3	Wed Jun 04 07:59:15 +0000 2008
@@ -1,64 +1,93 @@
 TEXT CONVERSION AND SUBSTITUTION:
 
+ # IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format
+ sed 's/.$//'               # assumes that all lines end with CR/LF
+ sed 's/^M$//'              # in bash/tcsh, press Ctrl-V then Ctrl-M
+ sed 's/\x0D$//'            # gsed 3.02.80, but top script is easier
+
+ # IN UNIX ENVIRONMENT: convert Unix newlines (LF) to DOS format
+ sed "s/$/`echo -e \\\r`/"            # command line under ksh
+ sed 's/$'"/`echo \\\r`/"             # command line under bash
+ sed "s/$/`echo \\\r`/"               # command line under zsh
+ sed 's/$/\r/'                        # gsed 3.02.80
+
+ # IN DOS ENVIRONMENT: convert Unix newlines (LF) to DOS format
+ sed "s/$//"                          # method 1
+ sed -n p                             # method 2
+
+ # IN DOS ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format
+ # Can only be done with UnxUtils sed, version 4.0.7 or higher.
+ # Cannot be done with other DOS versions of sed. Use "tr" instead.
+ sed "s/\r//" infile >outfile         # UnxUtils sed v4.0.7 or higher
+ tr -d \r <infile >outfile            # GNU tr version 1.22 or higher
+
  # 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 and 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
  sed 's/\(.*\)foo\(.*foo\)/\1bar\2/' # replace the next-to-last case
  sed 's/\(.*\)foo/\1bar/'            # replace only the last case
 
  # 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'
 
  # change "scarlet" or "ruby" or "puce" to "red"
  sed 's/scarlet/red/g;s/ruby/red/g;s/puce/red/g'   # most seds
  gsed 's/scarlet\|ruby\|puce/red/g'                # GNU sed only
 
  # reverse order of lines (emulates "tac")
  # bug/feature in HHsed v1.5 causes blank lines to be deleted
  sed '1!G;h;$!d'               # method 1
  sed -n '1!G;h;$p'             # method 2
 
  # 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/ /'
 
  # if a line ends with a backslash, append the next line to it
  sed -e :a -e '/\\$/N; s/\\\n//; ta'
 
  # if a line begins with an equal sign, append it to the previous line
  # and replace the "=" with a single space
  sed -e :a -e '$!N;s/\n=/ /;ta' -e 'P;D'
 
  # add commas to numeric strings, changing "1234567" to "1,234,567"
  gsed ':a;s/\B[0-9]\{3\}\>/,&/;ta'                     # GNU sed
  sed -e :a -e 's/\(.*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta'  # other seds
 
  # add commas to numbers with decimal points and minus signs (GNU sed)
  gsed ':a;s/\(^\|[^0-9.]\)\([0-9]\+\)\([0-9]\{3\}\)/\1\2,\3/g;ta'
 
  # add a blank line every 5 lines (after lines 5, 10, 15, 20, etc.)
  gsed '0~5G'                  # GNU sed only
  sed 'n;n;n;n;G;'             # other seds