适用于Bash编程初学者小例子

去掉字符串前面的一个或多个空格。

#!/bin/bash

str="f810yunlong-3:     Cache flushing complete.      "

IFS=':' read -ra substrs <<< "$str"
NODE="${substrs[0]}"
MSG="${substrs[1]}"

TRIM_MSG= echo "$MSG" | sed -e 's/^[[:space:]]*//'

#Remove the leading spaces from the variable
TRIM_MSG=`echo $MSG | sed -e 's/^[[:space:]]*//'`

# Print the value of $Var after trimming
printf "%s " "$NODE"
printf "=%s= " "$TRIM_MSG"

判断一个字符串里是否包含有一个子字符串。

#!/bin/bash

str="f810yunlong-3: Cache flushing complete.    "

if [[ "$str" == *"Cache flushing complete."* ]]
then
     printf "One node cache flushed successfully! "
else
     printf "[Error] "
     printf "Error happened in one node on flushing inline dedupe index and queue flush! "
fi

遍历一个文件夹里的所有的zip文件，以各自的zip文件名为各自的目录名，逐个解压到指定的目录下。

#!/bin/sh

ZIPDIR="/ifs/yunlong_bash/dir_zips"
UNZIPDIR="/ifs/yunlong_bash/dir5"

printf "Entered path: $ZIPDIR. "
cd "$ZIPDIR"

for zip in *.zip
do
   dirname=`echo $zip | sed 's/.zip$//'`
   printf "Directory name to extract this file is: %s. " $dirname
   dirfullpath="$UNZIPDIR/$dirname"
   printf "Directory full path to extract this file is：%s. " $dirfullpath
  
   mkdir "$dirfullpath"
   unzip $zip -d $dirfullpath
   printf " "
  
done

经过检验成功！

遍历一个文件夹里所有的tar文件，以各自的文件名为目录名，逐个解压到指定的目录下。

#!/bin/sh

TARDIR="/ifs/yunlong_bash/tar_test/tars"
UNTARDIR="/ifs/yunlong_bash/tar_test/untars"

printf "Entered path: $TARDIR. "
cd "$TARDIR"

for tar in *.tar
do
   dirname=`echo $tar | sed 's/.tar$//'`
   printf "Directory name to extract this file is: %s. " $dirname
   dirfullpath="$UNTARDIR/$dirname"
   printf "Directory full path to extract this file is：%s. " $dirfullpath
  
   mkdir "$dirfullpath"
   tar -xvf $tar -C $dirfullpath

  printf " "
  
done

经笔者亲自运行检验通过。

终止脚本的进一步执行。

#!/bin/bash

printf "Script is executing."
exit
printf "Script is still executing after exit."

*一试便知，第二句的打印终端上看不到的，因为没被执行。

逐行读取一个文本文件，并将内容输出。

#!/bin/bash
filename="/home/yunlong/source_datasets.txt"
n=1

while read line; do
# reading each line
echo "Line No. $n : $line"
n=$((n+1))
done < $filename

参考资料

===========

https://stackoverflow.com/questions/918886/how-do-i-split-a-string-on-a-delimiter-in-bash

https://linuxhint.com/trim_string_bash/

https://bash.cyberciti.biz/guide/Exit_command

https://linuxhint.com/read_file_line_by_line_bash/