How do I remove lines of a file which contain a specific string?

using sed

Run this command:

sed -i '/adf\.ly/d' inputfile 

man sed

   -i[SUFFIX], --in-place[=SUFFIX]
      edit files in place (makes backup if extension supplied)

Using grep

Thanks for @kos notes:

grep -v "ad\.fly" inputFile  > outputfile

The following will remove the lines containing "adf.ly" in filename.txt in-place:

sed -i '/adf\.ly/d' filename.txt

Use the above command without -i to test it before removing lines.

Using awk (thanks to terdon for the shortened version):

< inputfile awk '!/adf\.ly/' > outputfile

• < inputfile: redirects the content of inputfile to awk's stdin
• > outputfile: redirects the content of awk's stdout to outputfile

awk command breakdown:

• !/adf\.ly/: prints the record if not matching the adf\.ly regex

Using Perl (thanks to terdon for the shortened version):

< inputfile perl -ne '/adf\.ly/||print' > outputfile

• -n: places a while (<>) {[...]} loop around the script
• -e: reads the script from the arguments

Perl command breakdown:

• /: starts the pattern
• adf\.ly: matches an adf\.ly string
• /stops the pattern
• ||: executes the following command only if the pattern didn't match the line
• print: prints the line

Here is a bash one-liner:

while IFS= read -r i; do [[ ! $i =~ .*adf\.ly.* ]] && echo "$i"; done <file.txt

• Variable i will contain each line while iterating

• [[ $i =~ .*adf\.ly.* ]] checks if the line has the string adf.ly, ! negates the check so [[ ! $i =~ .*adf\.ly.* ]] will check if the line does not contain adf.ly

• If yes (&&), then the line will be printed.

To save the output to another file (out.txt):

while IFS= read -r i; do [[ ! $i =~ .*adf\.ly.* ]] && echo "$i"; done <file.txt >out.txt

You could use the standard text editor, ed:

printf '%s\n' 'g/adf\.ly/d' w q | ed file.txt

You can use Vim in Ex mode:

ex -sc 'g/adf\.ly/d' -cx hosts

1. g global search

2. d delete

3. x save and close