Replace whole line when match found with sed

Question

I need to replace the whole line with sed if it matches a pattern. For example if the line is \'one two six three four\' and if \'six\' is there, then the whole

Answer 1

This might work for you (GNU sed):

sed -e '/six/{c\fault' -e ';d}' file

or:

sed '/six/{c\fault'$'\n'';d}' file

Answer 2

Above answers worked fine for me, just mentioning an alternate way

Match single pattern and replace with a new one:

sed -i '/six/c fault' file

Match multiple pattern and replace with a new one(concatenating commands):

sed -i -e '/one/c fault' -e '/six/c fault' file

Answer 3

You can do it with either of these:

sed 's/.*six.*/fault/' file     # check all lines
sed '/six/s/.*/fault/' file     # matched lines -> then remove

It gets the full line containing six and replaces it with fault.

Example:

$ cat file
six
asdf
one two six
one isix
boo
$ sed 's/.*six.*/fault/'  file
fault
asdf
fault
fault
boo

It is based on this solution to Replace whole line containing a string using Sed

More generally, you can use an expression sed '/match/s/.*/replacement/' file. This will perform the sed 's/match/replacement/' expression in those lines containing match. In your case this would be:

sed '/six/s/.*/fault/' file

---

What if we have 'one two six eight eleven three four' and we want to include 'eight' and 'eleven' as our "bad" words?

In this case we can use the -e for multiple conditions:

sed -e 's/.*six.*/fault/' -e 's/.*eight.*/fault/' file

and so on.

Or also:

sed '/eight/s/.*/XXXXX/; /eleven/s/.*/XXXX/' file

Answer 4

To replace whole line containing a specified string with the content of that line

Text file:

Row: 0 last_time_contacted=0, display_name=Mozart, _id=100, phonebook_bucket_alt=2
Row: 1 last_time_contacted=0, display_name=Bach, _id=101, phonebook_bucket_alt=2

Single string:

$ sed 's/.* display_name=\([[:alpha:]]\+\).*/\1/'
output:
100
101

Multiple strings delimited by white-space:

$ sed 's/.* display_name=\([[:alpha:]]\+\).* _id=\([[:digit:]]\+\).*/\1 \2/'
output:
Mozart 100
Bach 101

Adjust regex to meet your needs

[:alpha] and [:digit:] are Character Classes and Bracket Expressions