Latest revision as of 19:31, 7 February 2013

sed is a command to edit a text stream in batch mode.

For example,

sed "s/a/o/"

Will read your input (stream) from the keyboard and substitute every a by an o.

Usecases

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

# echo "hello world" | sed "s/world/moon/"
hello moon

sed -i '1i <This is now at the first line>' <filename>

sed 's/\ \{1,\}/\ /g'

sed -ri "s/.{16}3200/sapdp00 3200/" /etc/services

You cannot use sed to delete linebreaks, for this you must use tr.

@@ Line 1: / Line 1: @@
-sed: Replace strings
+[[sed]] is a [[command]] to edit a text stream in [http://en.wikipedia.org/wiki/Batch_mode batch mode].
-  sed -e "s/cgi?\([0-9][0-9]*\)/cgi@\1.html/g" myfile.html > index.html
+For example,
+  sed "s/a/o/"
+Will read your input (stream) from the keyboard and '''s'''ubstitute every '''a''' by an '''o'''.
+= Usecases =
+* Remove leading white space
+ sed 's/^[ \t]*//'
+* Replace strings
+ # echo "hello world" | sed "<abbr title="substitute">s</abbr>/world/moon/"
+ hello moon
+* Insert a line a beginning of file
+ sed -i '1i <This is now at the first line>' <filename>
+* Replace several newlines by one
+ sed 's/\ \{1,\}/\ /g'
+* change the protocol for a given port in /etc/services:
+ sed -ri "s/.{16}3200/sapdp00 3200/" /etc/services
+= Limitations =
+You cannot use sed to delete linebreaks, for this you must use tr.
+= See also =
+* [[Bash Skripting Tutorial]]
+* [[piping]]
+* [[grep]]
+* [[regex]]