If you have necessary to find and remove a specific line from am file on Linux system use following different command,

For example the below command remove a line which contain a string,

# ​sed -i '/string-name/d' thelinuxfaq*.txt

The below command remove a line which contain a string, with a same file (thelinuxfaq.txt.backup)
 
# sed -i ".backup" '/test/d' thelinuxfaq.txt

Follwoing command just clear a line which contain a string,
 
# sed -i 's/linux//g' filename.txt

This command, find files  file names with .txt extension, remove a line which contain a string "linux"
 
find -name '*.txt' -exec sed -i=.bak '/linux/d' "{}" ';'

-i (or) --in-place edit files in place

GREP command also help us to remove a line, the below command are grep with -v option invert the sense of matching to select non-matching lines.
 
# cat new_file.txt


Linux

CentOS

RedHat

Fedora

Ubuntu
# grep -v "Ubuntu" new_file.txt > copied_file.txt

# cat copied_file.txt 


Linux

CentOS

RedHat

Fedora


Remove a file name which contain a string.

Find the files which contain string name "fedora" and remove that files.
 
# grep -ir 'fedora' *.txt


copied_file.txt:Fedora

new_file.txt:Fedora

testbak.txt:Fedora

 
# grep -ir 'fedora' *.txt | exec rm -rf *