shell miscellanies

 

1. #!/bin/sh
   
   echo "Num of arguments: $#"
   echo "Current PID: $$"
   echo "BASHPID: $BASHPID"
   sleep 10 &
   echo "The last deforegroud PID: $!"
   echo "The current shell options: $-"

    

2. shell中可以使用8进制转义序列
   格式必须为

   $'\octal'

   $号可以至于string前
   $"string" & "string" 无任何区别
   $'string' & 'string' 是有很大区别       'string' 原样输出, $'string' 会让string产生转义效果

   
   

    

   
   

   必须将"$IFS"用 ""包裹,否则shell会把 空格 "\t" 去掉

   xxd -b 二进制显示
   xxd -u 大写hexdecimal显示
   od -b  octal
   od -c characters

    

3. 颜色输出的函数
   

   #!/bin/sh
   #==== Colorized variables ====
   
   if [[ -t 1 ]];then # is terminal
           BOLD="\e[1m"; DIM="\e[2m";
           RED="\e[0;31m"; RED_BOLD="\e[1;31m";
           YELLOW="\e[0;33m"; YELLOW_BOLD="\e[1;33m";
           GREEN="\e[0;32m"; GREEN_BOLD="\e[1;32m";
           BLUE="\e[0;34m"; BLUE_BOLD="\e[1;34m";
           GREY="\e[37m"; CYAN_BOLD="\e[1;36m";
           RESET="\e[0m";
   fi
   
   function log() { echo -e "${GREY}# ${@}${RESET}"; }
   function title() { echo -e "${BLUE_BOLD}# ${*}${RESET}"; }
   function finish() { echo -e "\n${GREEN_BOLD}# Finish!${RESET}"; exit 0; }
   function userAbort() { echo -e "\n${YELLOW_BOLD} Abort! ${RESET}"; exit 0; }
   function success() { echo -e "${GREEN} Success: ${@} ${RESET}"; }
   function warn() { echo -e "${YELLOW_BOLD} Warning: ${*} ${RESET}"; }
   function error() { echo -e "${RED_BOLD} Error: ${RED}${@}${RESET}\n"; exit 1; }
   
   log uoiop bnm
   title uiop zxc
   success uioppp vbnm
   warn uioppp vbn
   userAbort "uoop"
   error 'parameter error'

   

    

4. echo {0..10..2}
   

    

    结果会使用0填充