Friday, 16 March 2018

sed Crib Sheet

sed (stream editor) is a linux command that can manipulate files.  It is particularly useful for doing match and replace on a whole file. Below is the linux syntax

Change from 'something' to 'something else

sample.txt

hello out
there
how are
you today


Simple single line match
> sed -i s/hello/goodbye/ sample.txt
goodbye out
there
how are
you today


Multiline replace.  Match on 'out'.  N adds the next line to the 'match space' and then there is a normal substitution on the 'match space'.
> sed -i "/out/{N;s/there/fred/}" sample.txt
hello out
fred
how are
you today

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