From c2fc594db46a9c1e0c6522f394805d81ce77b7af Mon Sep 17 00:00:00 2001
From: I-Man Ng <nim.1111.ou@gmail.com>
Date: Thu, 9 May 2019 15:41:47 +0800
Subject: [PATCH 1/4] Improve 'get the first character of variable

Thanks to Masta's command on Reddit
---
 README.md | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 5479404..3616e2c 100644
--- a/README.md
+++ b/README.md
@@ -1018,9 +1018,13 @@ echo ${#var}
 ```
 ##### get the first character of the variable
 ```bash
-var="some string"
+var=string
+echo "${var:0:1}"
+#s 
+
+#or
 echo ${var%%"${var#?}"}
-#s
+
 ```
 ##### remove the first or last string from variable
 ```bash

From 6ecd7cf784cabbad67d6ad6ca8a6b4ad56871515 Mon Sep 17 00:00:00 2001
From: I-Man Ng <nim.1111.ou@gmail.com>
Date: Thu, 9 May 2019 16:04:33 +0800
Subject: [PATCH 2/4] Fixed some typos and bugs

Thanks to Crestwave's correction on Reddit.
---
 README.md | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index 3616e2c..47709d4 100644
--- a/README.md
+++ b/README.md
@@ -44,8 +44,8 @@ Ctrl + d : if you've type something, Ctrl + d deletes the character under the cu
 Ctrl + k : delete all text from the cursor to the end of line.
 Ctrl + x + backspace : delete all text from the beginning of line to the cursor.
 Ctrl + t : transpose the character before the cursor with the one under the cursor, press Esc + t to transposes the two words before the cursor.
-Ctrl + w : delete the word before the cursor.
-Ctrl + u : delete the line before the cursor.
+Ctrl + w : cut the word before the cursor; then Ctrl + y paste it
+Ctrl + u : cut the line before the cursor; then Ctrl + y paste it
 Ctrl + x + Ctrl + e : launch editor define by $EDITOR
 ```
 ##### Change case
@@ -877,7 +877,7 @@ find . -type d
 ##### Edit all files under current directory (e.g. replace 'www' with 'ww')
     
 ```bash
-find . name '*.php' -exec sed -i 's/www/w/g' {} \;
+find . -name '*.php' -exec sed -i 's/www/w/g' {} \;
 ```
 if no subdirectory
     
@@ -944,7 +944,7 @@ if ((x >= 5)); then …
 if ((j==u+2))
 
 # Use [[ ]] for comparison
-if [[$age >21]]
+if [[ $age -gt 21 ]]
 ```
 
 [More if commands](http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_07_01.html)
@@ -1200,7 +1200,7 @@ curl https://transfer.sh/tG8rM/filename.txt -o filename.txt
 ```bash
 data=file.txt
 url=http://www.example.com/$data
-if [! -s $data];then
+if [ ! -s $data ];then
     echo "downloading test data..."
     wget $url
 fi
@@ -1495,7 +1495,12 @@ cp -rp /path/to/directory
 ##### Store current directory
     
 ```bash
-pushd . $popd ;dirs -l 
+pushd . 
+# then pop
+popd
+#pushd .
+#or use dirs to display the list of currently remembered directories. 
+dirs -l 
 ```
 
 ##### Show disk usage
@@ -2491,6 +2496,12 @@ echo -e ' \t '
 
 ##### Array
 ```bash
+declare -a array=()
+ 
+#or
+declare array=()
+ 
+#or associative array 
 declare -A array=()
 ```
 

From 7643e712fdb477db0298e868a37c229467883b35 Mon Sep 17 00:00:00 2001
From: I-Man Ng <nim.1111.ou@gmail.com>
Date: Thu, 9 May 2019 16:07:23 +0800
Subject: [PATCH 3/4] fixed typos

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 47709d4..da69e4f 100644
--- a/README.md
+++ b/README.md
@@ -1496,9 +1496,10 @@ cp -rp /path/to/directory
     
 ```bash
 pushd . 
+ 
 # then pop
 popd
-#pushd .
+ 
 #or use dirs to display the list of currently remembered directories. 
 dirs -l 
 ```

From bbd2974d41c501df7baea84a92710e4437f47273 Mon Sep 17 00:00:00 2001
From: I-Man Ng <nim.1111.ou@gmail.com>
Date: Thu, 9 May 2019 19:19:25 +0800
Subject: [PATCH 4/4] Fix typo

Thank Costin Stefan for the reminder
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index da69e4f..517e233 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ Ctrl + x + Ctrl + e : launch editor define by $EDITOR
 Esc + u
 # converts text from cursor to the end of the word to uppercase.  
 Esc + l
-# converts text from cursor to the end of the word to uppercase. 
+# converts text from cursor to the end of the word to case. 
 Esc + c
 # converts letter under the cursor to uppercase.
 ```