Examples of Linux shell scripts

Shell scripting is the most basic knowledge of our OPS management, and here are a few examples of my learning process (compared to Daniel). The purpose of this blog is to record the course of learning scripts, but also to be able to discuss learning with the reader.

# example1:  template   Script name for automatically creating scripts:creat_scripts.sh #  function Description: Creat_scripts.sh scripts_name   If the created script name file does not exist, create a script file;#  if the corresponding file exists and is a script file, open the file to the last line;#  if the corresponding file exists but is not a script file, you are prompted to exit. #!/bin/bash# description: create a script model# version: 0.0.1#  author: alex# date: 2014-07-09#  the problem of judging parameters if [ $# -lt 1 ];then         echo  "usage:  ' basename $0 '  scrpipt_name."         exit 2fiif [ ! -e  "$"  ];then/ bin/touch  "$" cat >  "$"  <<eof#!/bin/bash# description:# version:#  date:# author: Alex# license: GPLEOFvim +  "$" #  here to determine if the script is normally exited, Determine whether there is  . SCRIPTS_NAME.SWP hidden files if [ ! -e  "'/usr/bin/dirname $1 '. $1.swp"  ];then         [ !  -x $1 ] && /bin/chmod +x  "$"          bash -n $1 &>/dev/null        result =$?         [  $result  -ne 0 ] &&  echo  "$ (bash -n $1)"  fielse[[   '/usr/bin/file  "'  =~   bourne-again\ shell\ script\ text\ executable$ ]] && vim  +  "$  |" |  echo  "this is not scripts."  && exit 2if [ ! -e  "'/usr/bin/dirname $1 ' $1.swp"  ];then                 [ !  -x $1 ] && /bin/chmod +x  "$"                  bash -n $1 &>/dev/null                 result=$?                  [  $result  -ne 0 ] &&  echo  "$ (bash -n $1)"          fifi

# example2: To interpret whether a IP&NBSP;V4 address is a a,b,c class address, and if so, print out the default mask #  This script is created by Example1 script #!/bin/bash#  description:# version:0.0.0# date:2014-07-16# author: alex# license: gpl#  The following is the IP address decimal representation of the four-bit regular expression fistip= "[1-9]| [1-9] [0-9]|11[0-9]|12[1-68-9]|1[3-9][0-9]|2[0-1][0-9]|22[0-3] "secondip=" [0-9]| [1-9] [0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5] "thirdip=" [0-9]| [1-9] [0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5] "fourip=" [1-9]| [1-9] [0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4] "read -p " PLEASE&NBSP;INPUT&NBSP;IP&NBSP;ADDR: " ip_ addrwhile true ;d o         #  equivalent to   while  : ;d oif echo  "$ip _addr"  | grep -E  "^\< ($fistip) \>\.\< ($ SECONDIP) \>\.\< ($thirdip) \>\.\< ($fourip) \>$ " &>/dev/null;then#  The following sentence and above should have the same function, but in fact not, the author is studying #if [[  "$ip _addr"  =~ ^\<\ ($fistip \) \>\.\<\ ($ secondip\) \>\.\<\ ($thirdip \) \>\. \<\ ($fourip \) \>$ ]];thenifconfig eth0  $ip _addr &>/dev/nullhead_ip= ' echo   "$ip _addr"  | cut -d. -f1 ' if [  $head _ip -ge 1 -a  $head _ ip -le 126 ];thenecho  "$ip _addr mask is 255.0.0.0" elif [  $head _ip  -ge 128 -a  $head _ip -le 191 ];thenecho  "$ip _addr mask is  255.255.0.0 "elif [  $head _ip -ge 192 -a  $head _ip -le 223 ]; then                         echo  "$ip _addr mask is 255.255.255.0" Fiexit  3elseread -p  "PLEASE&NBSP;AGAIN&NBSP;INPUT&NBSP;IP&NBSP;ADDR:"  ip_addrfidone

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