Shell Tools and Scripting课后练习

1. rust@DESKTOP-L4PLVQ4:~/missing$ ls -lhat --color
   total 0
   -rw-r--r-- 1 rust rust    7 Mar 27 16:18 foo1
   drwxr-xr-x 1 rust rust 4.0K Mar 26 22:01 ..
   drwxr-xr-x 1 rust rust 4.0K Mar 26 18:55 .
   -rwxrwxrwx 1 rust rust   83 Mar 26 18:55 script.py
   drwxr-xr-x 1 rust rust 4.0K Mar 26 18:19 bar
   drwxr-xr-x 1 rust rust 4.0K Mar 26 18:19 foo
   -rw-r--r-- 1 rust rust    0 Mar 26 18:11 foo10
   -rw-r--r-- 1 rust rust    0 Mar 26 18:11 foo2
   drwxr-xr-x 1 rust rust 4.0K Mar 26 17:14 b

1. #marco.sh
   #!/bin/bash
   marco() {
       export MARCO=$(pwd)
   }
   polo() {
       cd "$MARCO"
   }

rust@DESKTOP-L4PLVQ4:~/missing/test$ source marco.sh
rust@DESKTOP-L4PLVQ4:~/missing/test$ cd ..
rust@DESKTOP-L4PLVQ4:~/missing$ marco
rust@DESKTOP-L4PLVQ4:~/missing$ cd
rust@DESKTOP-L4PLVQ4:~$ polo
rust@DESKTOP-L4PLVQ4:~/missing$

1. count=1
   
    while true
    do
        ./buggy.sh 2> out.log
        if [[ $? -ne 0 ]]; then
            echo "failed after $count times"
            cat out.log
            break
        fi
        ((count++))
   
    done