1 administrator@ubuntu:~$ string='hello world' administrator@ubuntu:~$ echo '$string' hello world administrator@ubuntu:~$ echo '$string' $string 双引号与未加引号作用一样,而单引号输出为其里面的内容。 2 administrator@ubuntu:~$ echo 'the current work directory is: `pwd`' the current work directory is: /home/administrator 反引号将其内的内容作为命令来执行。 3 (1) administrator@ubuntu:~$ mkdir bin administrator@ubuntu:~$ cd bin administrator@ubuntu:~/bin$ vi Param echo ' script name: ' echo $0 echo 'show arguments:' echo $* echo 'my process id:' echo $$ echo 'Did my script go with any errors?' echo $? (2) administrator@ubuntu:~/bin$ . Param script name: bash show arguments:
my process id: 2626 Did my script go with any errors?
(3) $0 指的是命令名,$*指的是所有参数,$$指脚本当前运行的进程的PID号,$?表示最后一个进程或命令的执行状态。 4 (1) administrator@ubuntu:~$ i=10 j=5 (2)administrator@ubuntu:~$ echo $((i*5-j)) 45 administrator@ubuntu:~$ expr $i\*5-$j 10*5-5 5 (1) administrator@ubuntu:~$ str1=abcd administrator@ubuntu:~$ str2='abcd ' administrator@ubuntu:~$ test '$str1' = '$str2' administrator@ubuntu:~$ echo $? 1 (2) administrator@ubuntu:~$ str1=1234 administrator@ubuntu:~$ str2=01234 administrator@ubuntu:~$ [ '$str1' -eq '$str2' ] |
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