add grep

linux/grep.md

@@ -0,0 +1,12 @@
+# Useful grep arguments
+## Search without case sensitivity
+`cat file.txt | grep -i "pattern"`
+## Add lines to match pattern
+### Before
+`cat file.txt | grep -B 3 "pattern"`
+### After
+`cat file.txt | grep -A 3 "pattern"`
+### Both
+`cat file.txt | grep -C 3 "pattern"`
+## Show line numbers with matches
+`cat file.txt | grep -n "pattern"`