awk, sed, xargs, bash

Posted 2021-02-08 yaoyaohust

http://ryanstutorials.net/

 

awk:

split($1, arr, “ ”)

 

sed:

sed -n ‘42p‘ file

sed ‘42d‘ file

sed ‘s/replace_pattern/replace_str/g‘ file

sed ‘/remove_pattern/d‘ file

sed -i file #(inplace)直接修改读取的文件内容，而不是输出到终端

 

xargs:

xargs -n1 -i cmd {} 

 

bash:

• $HOSTNAME - The hostname of the machine the script is running on.
• Single quotes will treat every character literally.
• Double quotes will allow you to do substitution (that is include variables within the setting of the value).
• read varNameRead input from the user and store it in the variable varName./dev/stdinA file you can read to get the STDIN for the Bash script
• $(( expression ))  Return the result of the expression.${#var}Return the length of the variable var.