sed tricks

These one-liners are collected from various sites and articles on web – see the list of Sources at the bottom of this posting.

• Deleting all empty lines from the input file:

  sed ‘/^$/d’ 

• In-place replacement:

  sed –i ‘/^$/d’ INPUTFILE

• In-place replacement with backup of original file:

  sed –ibak ‘/^$/d’ INPUTFILE

• In-place deletion of all occurences of a string in a file:

  sed –i ‘/WORDTOBEDELETED/d’

• How to replace the first occurrence only (of a string match) in a file, using sed

  sed '0,/THISSTRING/s//TOTHATSTRING/' INPUTFILE

• Append environment variable PATH with sed:

  sed -e '/^PATH/s/"$/:\/usr\/lib\/myprog\/bin"/g' -i /etc/environment

• Remove all whitespace from beinning of lines:

  sed 's/^[ \t]*//g' foo

• Deleting the / from all html files contained in current folder:

  sed -i ‘s/src=”\//src=”/g’ *.html

• Greedy matching:

  % echo "foobar" | sed 's///g'
  bar
  

• Non greedy matching:

  % echo "foobar" | sed 's/]*>//g'
  foobar
  

Sources:

• How do you delete empty lines using ‘sed’? – http://ksearch.wordpress.com/2010/09/25/delete-empty-lines-using-sed/
• How to replace the first occurrence only (of a string match) in a file, using sed – http://techteam.wordpress.com/2010/09/14/how-to-replace-the-first-occurrence-only-of-a-string-match-in-a-file-using-sed/
• Append environment variable PATH with sed (2010.09.09) – http://kdguntu.wordpress.com/2010/09/09/append-path/
• Unix tip #3: Introduction to Find, Grep, Sed – http://developmentality.wordpress.com/2010/09/07/unix-tip-3-introduction-to-find-grep-sed/
• util: sed for text parsing – http://zosim26.wordpress.com/2010/09/01/util-sed-for-text-parsing/
• To delete the / after the src From HTML Files – http://somepalli.wordpress.com/2010/08/05/to-delete-the-word-after-the-src-from-html-files/
• “sed – non greedy matching” by Christoph Sieghart (2008.07.08) – http://0x2a.at/b/sed–non-greedy-matching

References

• UNIX man pages : sed – http://unixhelp.ed.ac.uk/CGI/man-cgi?sed
• sed – http://www.opengroup.org/onlinepubs/007908799/xcu/sed.html
• “Sed – An Introduction and Tutorial” by Bruce Barnett – http://www.grymoire.com/Unix/Sed.html
• man sed (1posix) – stream editor – http://pwet.fr/man/linux/commandes/posix/sed
• Get better at awk/sed/grep – http://kristianrumberg.wordpress.com/2010/09/01/get-better-at-awksedgrep/

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Related here: Command line based text replace – https://eikonal.wordpress.com/2010/07/13/command-line-based-text-replace/.

Related here: Scripting languages – https://eikonal.wordpress.com/2010/06/15/awk-sed/ | Unix tricks – https://eikonal.wordpress.com/2011/02/15/unix-tricks/ | SED tricks – https://eikonal.wordpress.com/2010/10/05/sed-tricks/ | Memory of things disappearing > nmap stuff > getports.awk – https://eikonal.wordpress.com/2010/06/23/memory-of-things-disappearing-nmap-stuff-getports-awk/ | AWK – https://eikonal.wordpress.com/2011/09/30/awk/