如何声明字符串变量，并赋值？
#!/bin/bash
TARGET_CLUSTER_NODE_IP="10.245.110.69"
printf “%s \n” $TARGET_CLUSTER_NODE_IP
如何初始化一个字符串数组变量，并遍历输出其每一个字符串元素的值？
#!/bin/bash
declare -a string_array=("Hello world!" "How are you?" "Nice to meet you!" "How do you do?" )
# Read the array values with space
for str in "${string_array[@]}"; do
echo $str
done
如何SSH到另一台主机并在其上运行几个命令？
#!/bin/bash
# 先配置SSH的免密，之后执行此脚本
hostname
ssh root@10.245.110.69 'hostname; whoami; date'
hostname
如何使用IF语句比较字符串的值？
#!/bin/bash
string1="Hello World!"
string2="Hello Bash!"if [[ $string1 == "Hello World!" ]]
then
printf "Same! \n"
else
print "Different! \n"
fiif [[ $string2 = *"Bash"* ]]
then
printf "Contains word 'Bash'. \n"
else
printf "Does not contain the word. \n"
fi
如何把for语句放在一行里执行？
#!/bin/bash
# For statement in multiple lines
for((i=1;i<10;i+=2))
do
echo "Welcome $i times"
done
# For statement in one line
for((i=1;i<=10;i+=2)); do echo "Welcome $i times"; done
如何建立一个字符串数组，并且查看每一个字符串？
#!/bin/bash
declare -a flush_results
flush_results+=("1.Hello")
flush_results+=("2.World")
flush_results+=("3.Bash")
echo ${flush_results[0]}
echo ${flush_results[1]}
echo ${flush_results[2]}
echo ${flush_results[@]}
如何捕获一个命令的输出，并把输出存到一个变量里？
#!/bin/bash
declare OUTPUT=$(ssh root@10.111.111.111 isi_for_array isi_flush --dedupe-queue --dedupe-index )
# Output of command "#ssh root@10.111.111.111 isi_for_array isi_flush --dedupe-queue --dedupe-index":
#f810-4: Cache flushing complete.
#f810-3: Cache flushing complete.
#f810-2: Cache flushing complete.
#f810-1: Cache flushing complete.
#Show result in multi-lines
echo "$OUTPUT"
#Show result in one line
echo $OUTPUT
*为什么OUTPUT带不带双引号，区别这么大呢？
Jonathan Leffler解释如下：
“the difference is that (1) the double-quoted version of the variable (echo "$VARIABLE") preserves internal spacing of the value exactly as it is represented in the variable — newlines, tabs, multiple blanks and all — whereas (2) the unquoted version (echo $VARIABLE) replaces each sequence of one or more blanks, tabs and newlines with a single space. Thus (1) preserves the shape of the input variable, whereas (2) creates a potentially very long single line of output”
如何把用换行符“\n”分隔的一个大字符串，分割开，并存放到一个数组中？
#!/bin/bash
declare OUTPUT=$(ssh root@10.111.111.111 isi_for_array isi_flush --dedupe-queue --dedupe-index )
echo "$OUTPUT"
echo $OUTPUT
SAVEIFS=$IFS # Save current IFS
IFS=$'\n' # Change IFS to new line
names=($OUTPUT) # split to array $names
IFS=$SAVEIFS # Restore IFS
for ((j=0;j<4;j+=1)); do
printf "Current is line: $j. \n"
printf "%s \n" "${names[$j]}"
done
参考资料
=============
https://linuxconfig.org/bash-printf-syntax-basics-with-examples
https://linuxhint.com/bash_loop_list_strings/
https://www.shellhacks.com/ssh-execute-remote-command-script-linux/
https://wangchujiang.com/linux-command/c/awk.html
https://www.cnblogs.com/ggjucheng/archive/2013/01/13/2858470.html
https://ryanstutorials.net/bash-scripting-tutorial/bash-if-statements.php
https://*.com/questions/4277665/how-do-i-compare-two-string-variables-in-an-if-statement-in-bash
http://www.masteringunixshell.net/qa36/bash-how-to-add-to-array.html
https://www.cyberciti.biz/faq/linux-unix-bash-for-loop-one-line-command/
https://www.claudiokuenzler.com/blog/762/bash-multi-line-output-saved-one-line-variable
https://*.com/questions/24628076/bash-convert-n-delimited-strings-into-array/45565601