Shell Tips

菜单选择

#!/bin/bash
echo "which one do you want?"
select option in option1 option2 option3 option4;
do
 break
done
echo "You have selected $option"

用户输入

read -p "input a word :" word
if [ ! -n "$word" ] ;then
 echo "you have not input a word!"
else
 echo "the word you input is $word"
 read -p "input another word :" anotherword
if [ ! -n "anotherword" ] ;then
 echo "you have not input another word!"
 else
 echo "another word you input is $anotherword"
 fi
fi

输入参数

if [ -z "$1" ]; then
  echo "no param input"
else
  echo "$1"
fi

判断文件和文件夹

#!/bin/bash
if [ ! -e "/home/vagrant/abc" ];then
 echo "file or dir not exists."
else
 rm -rf /home/vagrant/abc
echo "file/dir removed."
fi

if [ ! -d "/home/vagrant/test" ];then
  mkdir /home/vagrant/test
else
  echo "dir exists."
fi

if [ ! -f "/home/vagrant/abc" ];then
 echo "file not exists."
else
 rm -f /home/vagrant/abc
echo "file removed."
fi

Usage

#!/bin/bash
if [ $# != 2 ] ; then
echo "USAGE: $0 file_path_1 file_path_2"
echo " e.g.: $0 /home/vagrant/abc /home/vagrant/efg"
exit 1;
fi

脚本路径

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
echo $SCRIPT_DIR

sed

替换: 
sed -i "s/string_a/string_b/g" file_path
替换的如果是路径（含有/)，则用|代替。注意要用双引号
str="/data/path"
sed -i "s|string_a|$str|g" file_path

eval

mycmd=’ls -all’
eval $mycmd #execute command