Help with variable substition in sed

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# 1  
Old 06-10-2011
Help with variable substition in sed


I'm a bit stuck trying to get my sed syntax quite right for what I'm trying to do.

I have a list of directories in a file and am trying to remove some of them using sed. I can do it if I specify the directory I want to remove in the sed command and escape the "/"s like so:

say I want to remove /home/fred/scripts from dirs.txt. This works:

mv dirs.txt dirs.old; sed -e '/\/home\/fred\/scripts/d' dirs.old > dirs.txt

However, I can't seem to do this same thing using a variable to represent the directory I want to remove. I've tried several different combinations of single and double quotes in my sed script section, but just can't quite seem to get the syntax right.

Anyone have any suggestions to try?

# 2  
Old 06-10-2011
Probably because of the /'s mucking things up. It sees an unescaped / and thinks the expression ought to end there, finds more junk after it and throws a syntax error. Use another char as sed's separator:
sed -e "#/home/fred/scripts#d"

You should be able to substitute variables directly into that.

I'd just use grep, though:
grep -v "/home/scripts/fred" < infile > outfile

This User Gave Thanks to Corona688 For This Post:
# 3  
Old 06-10-2011
Thanks Corona688! I had forgotten that I could use a different delimiter in sed. That looks much better than all my escape characters.

Your suggestion to use grep instead is also a good one. Thanks again!
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