Remove exactly one line in a file

I have a file that contains the following lines:

SUKsoft:
SUKsoft: App-Conduct_Risk_Comment
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW

How can I remove the line "SUKsoft:"?

This line could be in any place of the file (beginning as it is now, or in the middle).

Is there a command to do this?

Solution 1:

To remove the line use

sed -i '/SUKsoft:\s*$/d' your_file 

Example

% cat foo
SUKsoft: 
SUKsoft: App-Conduct_Risk_Comment   
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW

% sed -i '/SUKsoft:\s*$/d' foo

% cat foo                    
SUKsoft: App-Conduct_Risk_Comment   
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW

Solution 2:

Here are the steps to remove the desired line:

$ sed 's/SUKsoft: *$//' file.txt

SUKsoft: App-Conduct_Risk_Comment
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW

I am assuming file.txt contains the lines.

Or,

$ sed 's/SUKsoft: *$//; /^$/d' file.txt
SUKsoft: App-Conduct_Risk_Comment
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW

it does not leave any blank line.

To edit in the file you can use,

sed -i 's/SUKsoft: *$//' file.txt

or

sed -i 's/SUKsoft: *$//; /^$/d' file.txt

as per your need.

See A.B's answer where it is done in more compact manner. Thanks to Wildcard.

Solution 3:

grep searches for lines that satisfy a pattern. grep -v discards lines that satisfy a pattern.

grep -v '^SUKsoft: *$'

The pattern is: lines that start (^) with SUKsoft:, possibly followed by spaces but nothing else until the end of the line ($).

Solution 4:

Judging from your post't raw source there's no space or sequence of spaces after "SUKsoft:", however just to be on the safe side this command will take care of those if present.

Using Perl:

perl -ne '!/^SUKsoft: *$/&&print' input

• !/^SUKsoft:$/&&print: if the current line doesn't match the pattern ^SUKsoft: *$, which matches a line starting with SUKsoft: string followed by zero or more spaces, prints the line;

% cat input
SUKsoft:
SUKsoft: App-Conduct_Risk_Comment
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW
% perl -ne 'print unless /^SUKsoft: *$/' input
SUKsoft: App-Conduct_Risk_Comment
SUKsoft: App-Conduct_Risk_R
SUKsoft: App-Conduct_Risk_RW