# One-liner Commands
1\. 建立多個目錄
```shell
mkdir -p -v /home/josevnz/tmp/{dir1,anotherdir,similardir}
```
2\. 搜尋取代關鍵字
```shell
# With sed
sed -i 's#ORIGINAL_VALLUE#NEW_VALUE#g' myfile1 myfile2
# With perl
perl -p -i -e 's#ORIGINAL#NEW_VALUE#' myfile1 myfile2
```
3\. 臨時以網頁方式分享特定目錄
```shell
# Python is required
cd $mydir && python3 -m http.server 8888
```
4\. 臨時寫一個多行的檔案
```shell
cat</my/new/file
Line1
Line2
A $VARIABLE
DOC
```
或 Ctrl + D 結束離開
```shell
cat > testfile
This is a test
multiple lines
and here we go
```
5\. 在指定目錄裡搜尋包含特定關鍵字的檔案
```shell
# With grep
grep -R 'import' --include='*.java' --color MySourceCodeDir
# With find
find MySourceCodeDir/ -name '*.java' -type f -print| xargs \
grep --color 'import
```
6\. 用 watch 監控記憶體使用
```shell
watch -n 5 -d '/bin/free -m'
```
7\. 更新所有的 Git 套件庫
```shell
for i in */.git; do cd $(dirname $i); git pull; cd ..; done
```