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Ali Razmdideh
Asked: 2016-12-26 12:33:23 +0800 CST

How to remove one line from repository with sed

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My /etc/apt/sources.list contains this line :

deb http://downloads.sourceforge.net/project/xenlism-wildfire/repo deb/

I want to remove that line via sed in command line, so I tried this code but returns error !

$ sudo sed 's:deb http://downloads.sourceforge.net/project/xenlism-wildfire/repo deb/::g' /etc/apt/sources.list
sed: -e expression #1, char 75: unknown option to `s'

I guess the symbol : after http caused this error, but how can I fix it?

command-line

2 Answers

  1. Best Answer

    You can use any* symbol to delimit the search/replace strings which does not conflict with symbols in the strings, as long as you use it consistently, e.g.:

    sudo sed 's#deb http://downloads.sourceforge.net/project/xenlism-wildfire/repo deb/##g' /etc/apt/sources.list

    This reduces the need to escape a problematic character (which could be done using \ as an escape).

    *I am sure there are exceptions, especially if using older versions of sed, but I'm not aware of any limitations off hand.

    • 9

  2. Run like this:

    sudo sed -i '\%^deb http://downloads.sourceforge.net/project/xenlism-wildfire/repo deb%d' /etc/apt/sources.list

    The problems I fixed:

    • Use -i flag to modify the file in-place. Without that, the command would just print the output of sed to the screen, without updating the file.
    • Instead of using s/// to replace the line with empty string, I used the d command to delete the line.
    • For the pattern matching, instead of /.../, I used \%...%, because % doesn't appear in the pattern. With /, all occurrences of / would have to be replaced.

    Note that possibly a simpler filter might be good enough. For example if you know that xenlist-wildfire is unique in the file, then this simpler command will work too:

    sudo sed -i '/xenlism-wildfire/d' /etc/apt/sources.list

    Since in this example there is no /, I could use the simpler /.../ filter.

    (Thanks for @steeldriver for the improvement ideas.)

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