Reorganize common shell scripts for operation and maintenance frontline work

Hello, everyone ! I'm BOGO !

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1、 monitoring Nginx Access log 502 situation , And do the corresponding action

Suppose the server environment is lnmp, Recent visits often appear 502 The phenomenon , And 502 Error in restart php-fpm Disappear after service , So you need to write monitoring scripts , Once it appears 502, It will restart automatically php-fpm service .

# scene ：
#1. The path to access the log file ：/data/log/access.log
#2. Script loop , Every time 10 Check once per second ,10 The number of logs per second is 300 strip , appear 502 Not less than 10%（30 strip ） You need to restart php-fpm service 
#3. The restart command is ：/etc/init.d/php-fpm restart
#!/bin/bash
###########################################################
# monitoring Nginx Access log 502 situation , And do the corresponding action 
###########################################################
log=/data/log/access.log
N=30 # Set threshold 
while :do
 # Check the access log for the latest 300 strip , And statistics 502 The number of times 
    err=`tail -n 300 $log |grep -c '502" '` 
if [ $err -ge $N ] 
then
/etc/init.d/php-fpm restart 2> /dev/null 
# Set up 60s Delay prevention scripts bug Cause infinite restart php-fpm service 
     sleep 60
 fi
 sleep 10
 done

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2、 Assign the results to variables

Application scenarios ： You want to assign execution results or location parameters to variables , For later use .

Method 1：

for i in $(echo "4 5 6"); do
   eval a$i=$idone
echo $a4 $a5 $a6

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Method 2： Set the position parameter 192.168.1.1{1,2} Split into variables

num=0
for i in $(eval echo $*);do   #eval take {1,2} Decompose into 1 2
   let num+=1
   eval node${num}="$i"
done
echo $node1 $node2 $node3
# bash a.sh 192.168.1.1{1,2}
192.168.1.11 192.168.1.12

 Method 3：arr=(4 5 6)
INDEX1=$(echo ${arr[0]})
INDEX2=$(echo ${arr[1]})
INDEX3=$(echo ${arr[2]})

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3、 Batch modify file name

Example ：

# touch article_{1..3}.html
# lsarticle_1.html  article_2.html  article_3.html
 Purpose ： hold article Change it to bbs

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Method 1：

for file in $(ls *html); do
    mv $file bbs_${file#*_}
    # mv $file $(echo $file |sed -r 's/.*(_.*)/bbs\1/')
    # mv $file $(echo $file |echo bbs_$(cut -d_ -f2)

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Method 2：

for file in $(find . -maxdepth 1 -name "*html"); do
     mv $file bbs_${file#*_}done

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Method 3：

# rename article bbs *.html
 Delete the first five lines of a document that contain letters , At the same time to delete 6 To 10 All the letters contained in the row 

1） Prepare test files , The file named 2.txt

 The first 1 That's ok 1234567 No letters 
 The first 2 That's ok 56789BBBBBB
 The first 3 That's ok 67890CCCCCCCC
 The first 4 That's ok 78asdfDDDDDDDDD
 The first 5 That's ok 123456EEEEEEEE
 The first 6 That's ok 1234567ASDF
 The first 7 That's ok 56789ASDF
 The first 8 That's ok 67890ASDF
 The first 9 That's ok 78asdfADSF
 The first 10 That's ok 123456AAAA
 The first 11 That's ok 67890ASDF
 The first 12 That's ok 78asdfADSF
 The first 13 That's ok 123456AAAA

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2） The script is as follows ：

#!/bin/bash
###############################################################
 Delete the first five lines of a document that contain letters , At the same time to delete 6 To 10 All the letters contained in the row 
##############################################################
sed -n '1,5'p 2.txt |sed '/[a-zA-Z]/'d
sed -n '6,10'p 2.txt |sed s'/[a-zA-Z]//'g
sed -n '11,$'p 2.txt
# The end result is just a print on the screen , If you want to change the file directly , The output can be written to a temporary file , Replace with 2.txt Or use -i Options 

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4、 Count the current directory with .html Total size of files at the end

Method 1：

# find . -name "*.html" -exec du -k {} \; |awk '{sum+=$1}END{print sum}'

 Method 2：
```bash
for size in $(ls -l *.html |awk '{print $5}'); do
    sum=$(($sum+$size))
done
echo $sum

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5、 Scan host port status

#!/bin/bash
HOST=$1
PORT="22 25 80 8080"
for PORT in $PORT; do
    if echo &>/dev/null > /dev/tcp/$HOST/$PORT; then
        echo "$PORT open"
    else
        echo "$PORT close"
    fi
done
 use  shell  The number of letters in the print sample statement is less than 6 's words 

# Sample statements ：
#Bash also interprets a number of multi-character options.
#!/bin/bash
##############################################################
#shell The number of letters in the print sample statement is less than 6 's words 
##############################################################
for s in Bash also interprets a number of multi-character options.
do
 n=`echo $s|wc -c` 
 if [ $n -lt 6 ] 
 then
 echo $s
 fi
done

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6、 Enter the number and run the corresponding command

#!/bin/bash
##############################################################
# Enter the number and run the corresponding command 
##############################################################
echo "*cmd menu* 1-date 2-ls 3-who 4-pwd 0-exit "
while :
do
# Capture the value the user typed 
 read -p "please input number :" n
 n1=`echo $n|sed s'/[0-9]//'g`
# Null input detection  
 if [ -z "$n" ]
 then
 continue
 fi
# Non digital input detection  
 if [ -n "$n1" ]
 then
 exit 0
 fi
 break
done
case $n in
 1)
 date
 ;;
 2)
 ls
 ;;
 3)
 who
 ;;
 4)
 pwd
 ;;
 0)
 break
 ;;
    # Enter the number not 1-4 A hint of 
 *)
 echo "please input number is [1-4]"
esac

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