sed command to delete a string containing / ,\ characters

Question

I have a String

/abc/gef        \*(cse,fff)

to delete from a file,have to match the full string pattern,tried with

sed -i '//abc/gef        \*(cse,fff)/d' filename

but this ends in an error:

sed: -e expression #1, char xx: expected newer version of sed

I also tried the following options but didn't work:

sed -i '/\/abc\/gef        \*(cse,fff)/d' filename
sed -i 's|/abc/gef        \*(cse,fff)||g' filename

What is the right command for this?

Answer 1

The following works with GNU sed versions 4.5 and 4.7 and will delete any lines that contain the string:

sed '/\/abc\/gef        \\\*(cse,fff)/d' file

You have to use \ to escape the two instances of / in the string so that they aren't taken as the delimiter and * which otherwise expands to the character before it which is f. The latter will cause it not to match the string.

You can also use the s option which allows other characters as a delimiter if you only want to delete the string itself throughout the file and not the entire line:

sed 's|/abc/gef        \\\*(cse,fff)||g' file

That uses | as a delimiter so that you don't have to escape /.

To edit the file in place after you're sure that it does what you want, you can use -i like you have above:

sed -i '/\/abc\/gef        \\\*(cse,fff)/d' file

sed -i 's|/abc/gef        \\\*(cse,fff)||g' file

EDIT: I have updated the answer as the string in the question is different from what it was when originally posted.

Answer 2

The problem is that both \ (escape character) and * (0 or more) have a special meaning in regular expressions, so you need to escape them in order to use them as literal characters. Now, the way to escape something is to add a \ before it. So, in order for * to match a literal asterisk and not mean "0 or more", you would write \*. Similarly, to escape the \ you would write \\. Putting this together, we have:

$ cat file 
foo
bar
/abc/gef        \*(cse,fff)
baz

And:

$ sed '/\/abc\/gef        \\\*(cse,fff)/d' file 
foo
bar
baz

Note how I have also escaped the / since // is the match operator in sed. This is why we have /\/abc\/gef and not //abc/gef. The d at the end means "delete any line matching this pattern".

Answer 3

This sounds like a job for grep:

$ cat file
line 1
line 2
/abc/gef        *(cse,fff)
line 4

$ grep -Fxv '/abc/gef        *(cse,fff)' file
line 1
line 2
line 4