From 72e598c84227235f5f8612387b1ef64dc144f387 Mon Sep 17 00:00:00 2001
From: z3rOR0ne <z3rOR0ne@protonmail.com>
Date: Tue, 3 May 2022 03:55:58 -0700
Subject: [PATCH] copied table of grep_egrep from unix programming environment

---
 grep_egrep.txt | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 grep_egrep.txt

diff --git a/grep_egrep.txt b/grep_egrep.txt
new file mode 100644
index 00000000..d0fb7693
--- /dev/null
+++ b/grep_egrep.txt
@@ -0,0 +1,22 @@
+    ----------------- Table 4.1 -----------------
+     --- grep and egrep Regular Expressions ---
+          (decreasing order of precedence)
+
+c       any non-special character c matches itself
+\c      turn off any special meaning of character c
+^       beginning of line
+$       end of line
+.       any single character
+[...]   any one of characters in ...; ranges like a-z are legal
+[^...]  any single character not in ...; ranges are legal
+\n      what the n'th \(...\) matched (grep only)
+r*      zero or more occurrences of r
+r+      one or more occurrences of r (egrep only)
+r?      zero or one occurrences of r (egrep only)
+r1 r2   r1 followed by r2
+r1|r2   r1 or r2 (egrep only)
+\(r\)   tagged regular expression r (grep only); can be nested
+(r)     regular expression r (egrep only); can be nested
+
+        No regular expression matches a newline.
+