aix基础概念的问题，请教一下

第二题： True or false? When quoted metacharacters are used with find, the shell will first expand the wildcard then pass control to find.
Answer:
   False:
   command(find) expression:
       find path expression
   attenttion: expression(regular expression), not pattern matching
   Some commands,such as (e)grep, sed, awk, find and locate, use own regular expression which similar with pattern matching.
   Shell expanded before command execution.therefore, quote metacharacters with find is used to prevent shell expanded the string before find command can execute.收起

第三题：
有个文件，就是passwd.back：
root:!:0:0::/:/usr/bin/ksh
root:1:3:4:5:m:/p
root:2:9:3:8:n:q
daemon:!:1:1::/etc:
bin:!:2:2::/bin:
sys:!:3:3::/usr/sys:
adm:!:4:4::/var/adm:
uucp:!:5:5::/usr/lib/uucp:
guest:!:100:100::/home0/guest:
nobody:!:4294967294:4294967294::/:
lpd:!:9:4294967294::/:
lp:*:11:11::/var/spool/lp:/bin/false
invscout:*:6:12::/var/adm/invscout:/usr/bin/ksh
snapp:*:200:13:snapp login user:/usr/sbin/snapp:/usr/sbin/snappd
ipsec:*:201:1::/etc/ipsec:/usr/bin/ksh
nuucp:*:7:5:uucp login user:/var/spool/uucppublic:/usr/sbin/uucp/uucico
esaadmin:*:811:0::/home0/esaadmin:/usr/bin/ksh
jiang:!:202:0::/home0/jiang:/bin/bash
sshd:*:203:201::/var/empty:/usr/bin/ksh
ldap:*:204:1::/home0/ldap:/usr/bin/ksh
用grep命令列出uid在200-299之间的所有用户。

Answer:
$ cat passwd.back |grep "2[0-9][0-9]:"
(没有测试，自己试一下。不能写成$ cat passwd.back |grep "2[0-99]:"  //会把uid为2位（20~29）的也会抽取出来。)
To omit  ":" is done in "2[0-9][0-9]:" , the ":" is used for matching accurately.
":" is a separation in the file named passwd.back.
"2[0-9][0-9]:" also can be done.收起

第三题：
有个文件，就是passwd.back：
root:!:0:0::/:/usr/bin/ksh
root:1:3:4:5:m:/p
root:2:9:3:8:n:q
daemon:!:1:1::/etc:
bin:!:2:2::/bin:
sys:!:3:3::/usr/sys:
adm:!:4:4::/var/adm:
uucp:!:5:5::/usr/lib/uucp:
guest:!:100:100::/home0/guest:
nobody:!:4294967294:4294967294::/:
lpd:!:9:4294967294::/:
lp:*:11:11::/var/spool/lp:/bin/false
invscout:*:6:12::/var/adm/invscout:/usr/bin/ksh
snapp:*:200:13:snapp login user:/usr/sbin/snapp:/usr/sbin/snappd
ipsec:*:201:1::/etc/ipsec:/usr/bin/ksh
nuucp:*:7:5:uucp login user:/var/spool/uucppublic:/usr/sbin/uucp/uucico
esaadmin:*:811:0::/home0/esaadmin:/usr/bin/ksh
jiang:!:202:0::/home0/jiang:/bin/bash
sshd:*:203:201::/var/empty:/usr/bin/ksh
ldap:*:204:1::/home0/ldap:/usr/bin/ksh
用grep命令列出uid在200-299之间的所有用户。

Answer:
$ cat passwd.back |grep "2[0-9][0-9]:"
(没有测试，自己试一下。不能写成$ cat passwd.back |grep "2[0-99]:"  //会把uid为2位（20~29）的也会抽取出来。)收起

第一题：True or false? find's most important characteristic is its ability to travel up through the file tree hierarchy.
Answer：
False:find's most important characteristic is its ability to travel down subdirectories.(attention: travel down, not travel up)收起

呵呵，光剩下回复了，没有人真正的回答问题了，
呵，这个楼主没想到吧收起

给编辑成不要回复就能看了，这人真不知道咋想的！收起

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