Add Replace Pattern Across Many Files In A Project as a Unix TIL

Author: jbranchaud

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1301 TILs and counting..._
+_1302 TILs and counting..._
 
 ---
 
@@ -1296,6 +1296,7 @@ _1301 TILs and counting..._
 - [Provide A Fallback Value For Unset Parameter](unix/provide-a-fallback-value-for-unset-parameter.md)
 - [Remove A Directory Called `-p`](unix/remove-a-directory-called-dash-p.md)
 - [Repeat Yourself](unix/repeat-yourself.md)
+- [Replace Pattern Across Many Files In A Project](unix/replace-pattern-across-many-files-in-a-project.md)
 - [Run A Command Repeatedly Several Times](unix/run-a-command-repeatedly-several-times.md)
 - [Safely Edit The Sudoers File With Vim](unix/safely-edit-the-sudoers-file-with-vim.md)
 - [Saying Yes](unix/saying-yes.md)

unix/replace-pattern-across-many-files-in-a-project.md

@@ -0,0 +1,28 @@
+# Replace Pattern Across Many Files In A Project
+
+Let's say I have a bunch of files in the `db/migrate` directory of my project
+that contain a line of text I'd like to update. I want to replace all
+occurrences of `t.bigint` with `t.integer`.
+
+First, I can get an idea of the scope of the change by listing out all the
+files and lines where this pattern exists using
+[`ripgrep`](https://github.com/BurntSushi/ripgrep).
+
+```bash
+$ rg 't.bigint' db/migrate
+```
+
+I can visually do a quick scan to make sure I'm not picking up results with my
+pattern that weren't intended.
+
+Then, I can include the `--files-with-matches` flag to limit the `ripgrep`
+output to just filenames. Those filenames can be piped to `sed` (via `xargs`)
+which will do the pattern replacement.
+
+```bash
+$ rg --files-with-matches 't.bigint' db/migrate | \
+  xargs sed -i '' 's/t.bigint/t.integer/g'
+```
+
+This does an in-place (`-i ''`) edit of the files substituting (`s///g`)
+globally the occurrences of `t.bigint` for `t.integer`.