Tag: pattern

How do I find files that do not contain a given string pattern?

grep -riL "foo" .

This is the explanation of the parameters used on grep

     -L, --files-without-match
             each file processed.
     -R, -r, --recursive
             Recursively search subdirectories listed.

     -i, --ignore-case
             Perform case insensitive matching.

How to delete a specific line from a text file in command line on Linux?

sed -i '4d' ./file

Here, -i means edit the file in-place. d is the command to “delete the pattern space; immediately start next cycle”. 4 means the 4th line.

Remove the last line:

sed '$d' filename.txt

Remove all empty lines:

sed '/^$/d' ./file

or

sed '/./!d' ./file

Remove lines from 7 to 9:

sed '7,9d' ./file

Remove the line matching by a regular expression REGULAR:

sed '/REGULAR/d' ./file

For a simple example, remove the lines containing “oops”:

sed '/oops/d' ./file

How to give a pattern for new line in grep?

grep patterns are matched against individual lines so there is no way for a pattern to match a newline found in the input.

However you can find empty lines like this:

grep '^$' file
grep '^[[:space:]]*$' file # include white spaces