Learn your shell!
Piping grep into grep
I was spelunking my .bash_history and came across this little piece of awesome.
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.* | grep dovetail | grep -v .*\.css | grep -v dovetail\/dovetail | cut -d \: -f 1 | xargs gvim
Wow! So what the heck was I doing there? Lets walk through it.
So I’ve got a problem… I am OCD about where asset files are located in our project. It’s a complete mess and every time I complain about it…
“It will be too hard to go through the app and change all the paths…” 
“You under estimate my command line awesome-itude!” Turns out its not that hard of a problem, let me break it down. All of our asset imports are abstracted out into an extension method we call from our view
<% this.Asset("myasset"); %>
Perfect so I have something consistent to grep for
~/lecode> find source/ -type f
Find all the files in the source directory
~/lecode> find source/ -type f | grep -v " "
Pipe that into grep and inverse match any path with a space (-v)
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.*
xargs that path into grep and search each file for any lines containing `this.Asset*`
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.* | grep dovetail
I only care about asset calls that contain dovetail
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.* | grep dovetail | grep -v .*\.css
Inverse grep (-v) any lines containing .css
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.* | grep dovetail | grep -v .*\.css | grep -v dovetail\/dovetail
Inverse grep (-v) assets that start with dovetail/dovetail because those are correct.
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.* | grep dovetail | grep -v .*\.css | grep -v dovetail\/dovetail | cut -d \: -f 1
Notice how grep outputs the file path and then the match. We can use cut to parse the output on the “:” (-d \:) and take the first column (-f 1)
~/lecode> find source/ -type f | grep -v " " | xargs grep this\.Asset.* | grep dovetail | grep -v .*\.css | grep -v dovetail\/dovetail | cut -d \: -f 1 | xargs gvim
Now I have my file names, xargs that into gvim and it loads up a new instance of gvim with all the files I need to change in a buffer list. Now I can make my change and :bnext (buffer next) to the next file.
“It looks like you are trying to change a bunch of files… Want to use find and replace?” Deeerp
-Ryan
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