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Sed Substitution Cheatsheet

This is a comprehensive list of examples for the sed (stream editor command). This command is used to find, replace, refactor, and modify text.

Rohan MolloyRohan Molloy

Sed examples


A collection based mostly on stackexchange posts along with a few I threw together myself. Later, I will have a .bashrc file that contains a collection of regex patterns.

Note that the arguments for these functions are additional arguments passed to sed. Variables like $pattern $find $replace must be pre-defined.

Find and replace


Find and replace any match anywhere in the file


find_and_replace(){
sed 's/'$find'/'$replace'/g' $@
}

Find and replace on lines containing pattern


find_and_replace_on_lines() {
sed '/'$pattern'/'$find'/'$replace'/g' $@
}

Find and replace the first match


find_and_replace_first_match(){
sed 's/'$find'/'$replace'/' $@
}

Find and replace only on the last match


find_and_replace_last_match() {
sed 's/\(.*\)'$find'/'$replace'/' $@
}

Find and replace inside a range of lines


find_and_replace_inside_range() {
sed '$range s/'$find'/'$replace'/g' $@
} 

Find and replace outside a range of lines


find_and_replace_outside_range(){
sed '$range !s/'$find'/'$replace'/g' $@
}

Find and replace the nth instance in a line


find_and_replace_nth_instance(){
sed 's/'$find'/'$replace'/'$nth_instance'' $@
}

Find and replace if within matching $start and $end pattern


find_and_replace_within_start_end(){
sed -e '/'$start'/,/^'$end'/s/'$find'/'$replace'/g' $@
}

Printing lines based on pattern



print_line_matching_pattern(){
sed '/'$pattern'/!d' $@
}

print_line_preceeding_pattern() {
sed -n '/'$pattern'/{g;1!p;};h' $@ 
}

print_line_suceeding_pattern(){
sed -n '/'$pattern'/{n;p;}' 
}

print_line_matching_pattern_and_all_subsequent(){
sed '/'$pattern'/,$!d' $@
}

print_line_matching_pattern_with_context(){
sed -n -e '/'$pattern'/{=;x;1!p;g;$!N;p;D;}'
}

print_lines_matching_patterns_in_any_order(){
sed '/'$pattern3'/!d; /'$pattern1'/!d; /'$pattern2'/!d' $@
}

print_lines_matching_patterns_in_specific_order(){
sed '/'$pattern1'.*'$pattern2'.*'$pattern3'/!d' $@
}

print_lines_min_nchars(){
sed -n '/^.\{$nchars\}/p' $@
}

print_lines_max_nchars(){
sed -n '/^.\{$nchars\}/!p' $@ 
}

print_substring_after_matching_pattern(){
sed -n -e 's/^.*'$pattern' //p' $@
}

print_word_after_matching_pattern(){
sed -n -e 's/^.*'$pattern' //p' $@
}

Translation/Refactoring


Comment all lines


comment_all_lines(){
sed '/s/^/#/g' $@
}

Comment lines from $start to $end


comment_lines_from_start_to_end(){
sed "$start,$end {s/^/#/}"  $@
}

Uncomment lines from $start to $end


uncomment_lines_from_start_to_end(){
sed "$start,$end {s/'^#'//}"  $@
}

Uncomment lines matching pattern


uncomment_lines_matching_pattern(){
sed '/'$pattern'/s/^/#/g' $@
}

Uncomment all lines


uncomment_all_lines(){
sed 's/^#//g'  $@
}

Change word to uppercase if matching pattern


change_word_matching_pattern_to_uppercase(){
sed -r "s/\<'$pattern'[a-z]+/\U&/g" $@   
}

Join two lines if the first ends in a backslash


join_two_lines_backslash(){
sed ':a; /\$/N; s/\\n//; ta'  $@
}

Remove characters in set from lines


set="[0-9]"
sed 's/'$set'//g' 

Insert strings $before and $after to lines matching pattern


sed '/'$pattern'/s@^.*$@'$before'&'$after'@g'

Paragraphing


Sort paragraphs alphabetically


sort_paragraphs_alphabetically(){
(sed '/./{H;d;};x;s/\n/={NL}=/g'| sort | sed '1s/={NL}=//;s/={NL}=/\n/g')
}

print_paragraph_containing_pattern(){
sed '/./{H;$!d;};x;/'$pattern'/!d' $@
}

Insert blank line below lines that match pattern


insert_linebreak_below_matching_lines(){
sed '/'$pattern'/G' $@
}

Insert blank line above lines that match pattern


insert_linebreak_above_matching_lines(){
sed '/'$pattern'/{x;p;x;}' $@
}

Insert blank line above and below matching lines


insert_linebreak_between_matching_lines(){
sed '/'$pattern'/{x;p;x;G;}' $@
}

Delete the last line of each paragraph


delete_last_line_of_each_paragraph(){
sed -n '/^$/{p;h;};/./{x;/./p;}' $@
}

print_every_nthline_starting_with_linex(){
sed -n '$nthline~$linexp' $@
}

Deleting lines


Delete lines matching pattern


delete_lines_matching_pattern(){
sed '/'$pattern'/d' $@
}

Delete all blank lines


delete_all_blank_lines(){
sed '/./!d' $@
}

Delete all blank/whitespace lines


delete_all_blank_whitespace_lines(){
sed "/^\s*$/d" $@
}

Delete all consecutive blank lines except for end


delete_all_consecutive_blank_lines_except_end(){
sed '/./,/^$/!d' $@
}

Delete all consecutive blank lines except start


delete_all_consecutive_blank_lines_except_start(){
sed '/^$/N;/\n$/D' $@
}

Delete all consecutive blank lines except for the first two


sed '/^$/N;/\n$/N;//D' 

Delete all trailing blank lines


sed -e :a -e '/^\n*$/{$d;N;};/\n$/ba' 

Delete every nth line after $start


sed '"$start"~"$nth"d' 

Delete all leading blank lines


sed '/./,$!d' 

Miscellaneous


Read lines from bottom-to-top (tac)


read_lines_bottom_to_top(){
sed '1!G;h;$!d' $@
}

Read lines from right to left (rev)


read_lines_right_to_left(){
sed '/\n/!G;s/\(.\)\(.*\n\)/&/;//D;s/.//' $@
}

Number lines - delimiting with tab


number_lines_tab_delimited(){
sed = $@ | sed 'N;s/\n/\t/' $@

}

Remove HTML tags


remove_html_tags(){
sed -e :a -e 's/<[^>]*>//g;/</N;//ba' $@
}

Join a relative and absolute path


join_pathAbsolute_with_pathRelative(){
sed 's@'$pathAbsolute'@&'/$pathRelative'@g' $@
}
Author

Rohan Molloy

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