Merge branch 'master' into master

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I-Man Ng 2019-05-09 19:25:30 +08:00 committed by GitHub
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@ -43,6 +43,8 @@ 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 : 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
@ -50,7 +52,7 @@ Ctrl + x + Ctrl + e : launch editor define by $EDITOR
Esc + u
# converts text from cursor to the end of the word to uppercase.
Esc + l
# converts text from cursor to the end of the word to uppercase.
# converts text from cursor to the end of the word to case.
Esc + c
# converts letter under the cursor to uppercase.
```
@ -874,7 +876,7 @@ find . -type d
##### Edit all files under current directory (e.g. replace 'www' with 'ww')
```bash
find . name '*.php' -exec sed -i 's/www/w/g' {} \;
find . -name '*.php' -exec sed -i 's/www/w/g' {} \;
```
if no subdirectory
@ -941,7 +943,7 @@ if ((x >= 5)); then …
if ((j==u+2))
# Use [[ ]] for comparison
if [[$age >21]]
if [[ $age -gt 21 ]]
```
[More if commands](http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_07_01.html)
@ -1015,9 +1017,13 @@ 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
@ -1193,7 +1199,7 @@ 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
@ -1488,7 +1494,13 @@ cp -rp /path/to/directory
##### Store current directory
```bash
pushd . $popd ;dirs -l
pushd .
# then pop
popd
#or use dirs to display the list of currently remembered directories.
dirs -l
```
##### Show disk usage
@ -2484,6 +2496,12 @@ echo -e ' \t '
##### Array
```bash
declare -a array=()
#or
declare array=()
#or associative array
declare -A array=()
```