[bash] Search a string in a file and delete it from this file by Shell Script

I want to delete a line containing a specific string from the file. How can I do this without using awk? I tried to use sed but I could not achieve it.

This should do it:

sed -e s/deletethis//g -i *
sed -e "s/deletethis//g" -i.backup *
sed -e "s/deletethis//g" -i .backup *

it will replace all occurrences of "deletethis" with "" (nothing) in all files (*), editing them in place.

In the second form the pattern can be edited a little safer, and it makes backups of any modified files, by suffixing them with ".backup".

The third form is the way some versions of sed like it. (e.g. Mac OS X)

man sed for more information.

Try the vim-way:

ex -s +"g/foo/d" -cwq file.txt

sed -i '/pattern/d' file

Use 'd' to delete a line. This works at least with GNU-Sed.

If your Sed doesn't have the option, to change a file in place, maybe you can use an intermediate file, to store the modification:

sed '/pattern/d' file > tmpfile && mv tmpfile file

Writing directly to the source usually doesn't work: sed '/pattern/d' file > file so make a copy before trying out, if you doubt it.