[colug-432] Tutorials

Scott Merrill skippy at skippy.net
Thu May 14 14:51:33 EDT 2015


> On May 14, 2015, at 2:45 PM, Steve VanSlyck <s.vanslyck at postpro.net> wrote:
> 
> I have a file,
> 
> /path/to/file_config
> 
> which is X lines long and one of the lines, location unknown, says,
> 
> Setting=No
> 
> What I want to do is write a simple bash script that will open that file, locate that line, change it to a comment, and then insert another line below it, with the end result looking like this:
> 
> # Setting=No
> Setting=Yes
> 
> Imagine I am your willing but unlettered intern. You're willing to teach me but would prefer, obviously, that I teach myself. Always better that way.
> 
> Is there a tutorial that you would recommend?
> 

The script you’re looking to create is already written.  It’s a tool called sed.  sed is the “stream editor”.  You can pipe files into it, and it can spit out edited versions based on commands you define.

sed is very  powerful.  The man page is likely not of particular help to you as you get started learning it.  Instead, I’d consult your favorite search engine for “sed tutorial” or similar, and work through a few of them.

Another useful tool is awk.  awk is also powerful, but can feel like an arcane spell at times.

Take your time learning both of these tools.  They’ll become indispensable for you as you grow more and more familiar with Linux!

Cheers,
Scott





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