1. IT244 - Introduction to Linux / Unix Instructor: Bo Sheng
The sed Editor(ch 13)
IT244 - Introduction to Linux / Unix
Instructor: Bo Sheng

2. What is sed Stream editor Syntax 1974, by bell lab Cousin to AWK
sed program [file-list]
sed -f program-file [file-list]

3. sed Program Basic syntax Address Instruction Line number
[address[,address]] instruction [argument-list]
Address
Line number
Regular expression
Instruction
Print (p)
Append (a), insert (i), change (c)
Write (w)
Quit (q)

4. Examples ~it244/it244/scripts/lines sed ‘/line/ p’ lines
By default, sed sends all lines to stdout.
sed -n ‘/line/ p’ lines
sed -n ‘3,6 p’ lines
sed ‘5 q’ lines

5. Examples Append (a) Insert (i) Change (c) ~it244/it244/scripts/append
sed –f append lines
Insert (i)
~it244/it244/scripts/insert
sed –f insert lines
Change (c)
~it244/it244/scripts/change
sed –f change lines

6. Examples Substitute (s) ~it244/it244/scripts/subs sed –n –f subs lines
s/search-string/replacement-string/[g][p][w]
g:global, p:print, w:write to files
~it244/it244/scripts/subs
sed –n –f subs lines
~it244/it244/scripts/sub_write
sed –f sub_write lines
cat temp

7. Examples Write (w) Next (n) Cleanup sed '2,4 w temp2' lines
~it244/it244/scripts/next
sed –n –f next lines
Cleanup
sed ‘s/ *$//’ file_ex

8. Hold Space Between hold space and pattern space Example
g:copy from HS to PS
G:copy from HS to PS and append a newline
h:copy from PS to HS
H:copy from PS to HS and append a newline
x:exchange the contents of PS and HS
Example
sed ‘G’ lines
sed –nf s1 lines