Shell脚本命令

#！/bin/bash
next_tips()  #$0代表当前文件名 $1第一个参数 $2 第2个参数 ....
{
  echo "---------$1-------------------"
}

next_tips "global or local varialbe test"

#变量赋值左右两边不能有空格
var_test()
{
  # local 局部变量
  echo "global v1:$v1"
  local v1="456"
  echo "local v1:$v1"
}

v1="123"
var_test
echo "global2 v1:"${v1}

next_tips "external varialbe test"
# $0 脚本文件名称 $1 第一个参数 $2 第二个参数
# $# 参数个数
# $? 前一个命令或函数返回的状态码
# $* 将所有参数通过字符串返回
# $$ 返回本进程PID
external_fun()
{
   #$0 $#（参数个数) $?（上个命令状态码) $*（打印所用参数）
   echo "parms total:$#"
   echo "func name:$0"
   test 1 -eq 2
   echo "the return code:$?"
   test 1 -ne 2
   echo "the return code:$?"
   echo "all parms is:$*"
   echo "the pid is :$$"
}
external_fun a b c d e f g

next_tips "system vaiable test"
# PATH HOME LOGNAME SHELL PWD
system_var_func()
{
  # PATH HOME LOGNAME SHELL PWD
   echo "PATH is:$PATH"
   echo "HOME is:$HOME"
   echo "LOGNAME is:$LOGNAME"
   echo "SHELL is:$SHELL"
   echo "PWD is:$PWD"
}
system_var_func

next_tips "vaiable operate test"
# "${}" 可输出值
# '${}' 不可输出值，继续打印${}
# `pwd` 反引号，推荐使用$()
# \  注释部分
specail_func()
{
  var1="binfire"
  echo "binfire var:${var1}"
  echo 'binfire var:${var1}'
  echo `pwd`
  echo $(pwd)
  echo "hello,\"binfire\""
}
specail_func

next_tips "condition string test"
# 检测测试表达式，如果成立返回0，否则返回非0
# 检测表达式有两种方式 test 或 [] 必须要用空格分开
# 字符串 = != -z (空字符串） -n (非空字符串)
# 数值 -eq -ne -gt -lt -ge -le
# 文件 -e -d (目录) -f(常规文件) -w -x -r -L(链接文件) -u (设置了suid)
# 逻辑运算符 ! -a (all) -o (or)

condition_string_test()
{
  # 字符串 = != -z (空字符串） -n (非空字符串)
  a="11"
  b="11"
  test "$a" = "$b"
  echo "a=b:$?"
  test "$a" != "$b"
  echo "a!=b:$?"
  test -z $a
  echo "a为空:$?"
  test -n $a
  echo "a不为空:$?"
}
condition_string_test

next_tips "condition int test"

condition_int_test()
{
  # 数值 -eq -ne -gt -lt -ge -le
  a=1
  b=1
  test "$a" -eq "$b"
  echo "a=b:$?"
  test "$a" -ne "$b"
  echo "a!=b:$?"
  test "$a" -lt "$b"
  echo "a<b:$?"
  test "$a" -gt "$b"
  echo "a>b:$?"
  test "$a" -le "$b"
  echo "a<=b:$?"
  test "$a" -ge "$b"
  echo "a>=b:$?"
}
condition_int_test

next_tips "condition file test"

condition_file_test()
{
  # 文件 -e -d (目录) -f(常规文件) -w -x -r -L(链接文件) -u (设置了suid)
  test -e /e/expr/shell/var.sh
  echo "file exists:$?"
  test -d /e/expr/shell
  echo "dir exists:$?"
  test -f /e/expr/shell/var.sh
  echo "file attr-normal:$?"
  test -w /e/expr/shell/var.sh
  echo "file attr-w:$?"
  test -x /e/expr/shell/var.sh
  echo "file attr-x:$?"
  test -r /e/expr/shell/var.sh
  echo "file attr-r:$?"
  test -L /e/expr/shell/var.sh
  echo "file attr-L:$?"
  test -u /e/expr/shell/var.sh
  echo "file attr-u:$?"
}
condition_file_test

next_tips " -a -o ! test "
condition_and_or_test()
{
   # -a (and) -o (or)
   test 3 -eq 3 -a 4 -eq 4
   echo "and test:$?"
   test 3 -eq 4 -o 4 -eq 4
   echo "or test:$?"
   test ! 3 -eq 3
   echo "! test:$?"
}
condition_and_or_test

next_tips " if xxx; then elif else if xxx then; fi"
ifelse_test()
{
  #请输入个分数；分数必须>=0或<=100,如果输入错误，重新输入； A>=90 B >=80 C>=70 D>=60 E<60
  echo "please input a score need ge 0 and le 100"
  read score
  while test "$score" -lt 0 -o "$score" -gt 100
  do
    echo "input error,please input a score need ge 0 and le 100"
    read score
  done

  if test "$score" -ge 90; then
    echo "A"
  elif test "$score" -ge 80; then
    echo "B"
  elif test "$score" -ge 70; then
    echo "C"
  elif test "$score" -ge 60; then
     echo "D"
  else
    echo "E"
  fi

}
ifelse_test

next_tips " exit 状态码测试"
exit_test()
{
  echo "hello,world"
  echo "$?"
  #exit 100  #返回码<255,外部接收时候即返回100
}
exit_test
echo "$?"

next_tips "case in ) esac"
case_test()
{
  read num
  case $num in
    1)
      echo "1"
      ;;
    2)
      echo "2"
      ;;
    3)
      echo "3"
      ;;
  esac
}
case_test

next_tips "int operate test"
int_test()
{
  a=1
  b=2
  let c=a+b
  echo "c=$c"
  let c=c-a
  echo "c=$c"
  let c=c*a
  echo "c=$c"
  let c=c/a
  echo "c=$c"
  let c=c**2  #2次方
  echo "c=$c"
  let c=c%a
  echo "c=$c"
}
int_test

next_tips " for while brek continue"
forwhilebreakcontinue_test()
{
  for((i=1;i<=5;i++))  #带个双括号
  do
    echo $i
  done
  #------
  for file in $(ls)
  do
    echo $file
  done
  #------
  i=1
  while test $i -lt 5
  do
    echo "$i"
    if test $i -eq 3 ; then
          echo "fk will break"
          break
        fi
    if test $i -eq 1 ; then
      echo "fk will continue"
      let i=i+1
      echo "now i:$i"
      continue
    fi
    let i=i+1
  done
}
forwhilebreakcontinue_test

read