Update cheatsheets

comm

@@ -0,0 +1,29 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# comm
+
+> Select or reject lines common to two files. Both files must be sorted.
+> More information: <https://www.gnu.org/software/coreutils/comm>.
+
+- Produce three tab-separated columns: lines only in first file, lines only in second file and common lines:
+
+`comm {{file1}} {{file2}}`
+
+- Print only lines common to both files:
+
+`comm -12 {{file1}} {{file2}}`
+
+- Print only lines common to both files, reading one file from `stdin`:
+
+`cat {{file1}} | comm -12 - {{file2}}`
+
+- Get lines only found in first file, saving the result to a third file:
+
+`comm -23 {{file1}} {{file2}} > {{file1_only}}`
+
+- Print lines only found in second file, when the files aren't sorted:
+
+`comm -13 <(sort {{file1}}) <(sort {{file2}})`