Linux example of sed

* sed: Stream EDitor

1. search and print

sed -n 'asdf/p' file

: Read file line by line without print (-n), and print a line if asdf is found.

2. substitution

sed 's/asdf/qwer/' file

: replace asdf by qwer, and does not change original file. just print

sed 's/asdf/qwer/' file > copyfile

: replace asdf by qwer, and copy file to copyfile

sed -i 's/asdf/qwer/' file

: replace asdf by qwer and change original file


If you would like to do for entire file, using '/g'.

sed -i 's/asdf/qwer/g' file

: replace asdf by qwer for entire file, and change original file


Thanks,

JF