SED

Delimiters

• Common delimiters: /, #, |, @

Delimiter	Notes
/	default, most common
#	great for paths/URLs
@	readable in scripts
\|	good for nested slashes
:	safe everywhere
~	nice visually
%	rarely used but valid
!	valid
,	valid

Flags

• -i = edit in file (instead of printing content to stdout)

Replacement Flags

• /g = global (all occurrences in line, not just first)
• // = replace with nothing

Replacement Syntax

s<delimiter>pattern<delimiter>replacement<delimiter>flags

File Replacement

sed -i "s/oldtext/newtext/g" filename.txt

String Replacement Example

echo "hello1x hello2x" | sed 's#hello#bye#g'

output: "bye1x bye2x"

Regex

File Extension Replacement

echo "filename.tar.gz" | sed 's|\..*||g'

output: "filename"

String Strip Example

echo "   hello world   " | sed 's@^[ ]*@@g' | sed 's@[ ]*$@@g'

output: "hello world"