5標準IO和管道-案例分析
阿新 • • 發佈：2020-08-07
1.將/etc/issue檔案中的內容轉換為大寫後儲存至/tmp/issue.out檔案中
[root@localhost etc]# tr a-z A-Z </etc/issue >/tmp/issue
[root@localhost etc]# cat /tmp/issue
\S
KERNEL \R ON AN \M
2.將當前系統登入使用者的資訊轉換為大寫後儲存至/tmp/who.out檔案中
[root@localhost etc]# w 17:36:52 up 3 days, 22 min, 2 users, load average: 0.00, 0.01, 0.05 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT root tty1 Mon17 3days 0.06s 0.06s -bash root pts/0 10.0.0.110 Tue14 4.00s 1.43s 0.29s w [root@localhost etc]# w|tr a-z A-Z >/tmp/who.out [root@localhost etc]# cat /tmp/who.out 17:38:27 UP 3 DAYS, 24 MIN, 2 USERS, LOAD AVERAGE: 0.00, 0.01, 0.05 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT ROOT TTY1 MON17 3DAYS 0.06S 0.06S -BASH ROOT PTS/0 10.0.0.110 TUE14 3.00S 1.15S 0.00S W
3.一個linux使用者給root發郵件，要求郵件標題為”help” ，郵件正文如下：
Hello, I am 使用者名稱,The system version is here,please help me to check it ,thanks!
作業系統版本資訊
[root@localhost data]# su linux [linux@localhost data]$ mail -s 'help' root@localhost << EOF > Hello,I am $USER,The system version is here,please help me to check it,thanks! > `uname -a` > EOF [linux@localhost data]$ exit exit [root@localhost data]# mail Heirloom Mail version 12.5 7/5/10. Type ? for help. "/var/spool/mail/root": 2 messages 2 new >N 1 [email protected] Thu Aug 6 17:50 19/697 "help" N 2 [email protected] Thu Aug 6 17:51 19/802 "help" & 2 Message 2: From [email protected] Thu Aug 6 17:51:06 2020 Return-Path: <[email protected]> X-Original-To: root@localhost Delivered-To: [email protected] Date: Thu, 06 Aug 2020 17:51:06 +0800 To: [email protected] Subject: help User-Agent: Heirloom mailx 12.5 7/5/10 Content-Type: text/plain; charset=us-ascii From: [email protected] Status: R Hello,I am linux,The system version is here,please help me to check it,thanks! Linux localhost.localdomain 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux & exit
4.將/root/下檔案列表，顯示成一行，並檔名之間用空格隔開
[root@localhost ~]# ls -a|tr '\n' ' '
. .. acl.txt anaconda-ks.cfg .bash_history .bash_logout .bash_profile .bashrc .cshrc .lesshst .tcshrc .viminfo .vimrc
5.計算1+2+3+...+99+100的總和
[root@localhost ~]# echo {1..100}|tr ' ' +|bc
5050
6.刪除Windows文字檔案中的回車字元 ，即“\r”
[root@localhost data]# hexdump -C f4.txt 00000000 61 61 61 0d 0a 62 62 62 0d 0a 62 62 62 0d 0a 63 |aaa..bbb..bbb..c| 00000010 76 63 63 0d 0a 64 64 64 0d 0a 77 65 6c 63 6f 6d |vcc..ddd..welcom| 00000020 65 20 74 6f 20 68 69 6e 73 61 6e 67 |e to hinsang| 0000002c [root@localhost data]# file f4.txt f4.txt: ASCII text, with CRLF line terminators [root@localhost data]# tr -d '\r' < f4.txt aaa bbb bbb cvcc ddd welcome to hinsang
7.處理字串“xt.,l 1 jr#!$mn 2 c*/fe 3 uz 4”，只保留其中的數字和空格
[root@localhost data]# echo 'xt.,l 1 jr#!$mn 2 c*/fe 3 uz 4'|tr -dc '[[:digit:]][[:space:]]'
1 2 3 4
8.將PATH變數每個目錄顯示在獨立的一行
[root@localhost ~]# echo $PATH|tr ':' '\n'
/usr/local/sbin
/usr/local/bin
/usr/sbin
/usr/bin
/root/bin
9.將指定檔案中0-9分別替代成a-j
[root@localhost data]# seq 0 9 > f1.txt
[root@localhost data]# cat f1.txt
0
1
2
3
4
5
6
7
8
9
[root@localhost data]# cat f1.txt|tr '0-9' 'a-j'
a
b
c
d
e
f
g
h
i
j
10.將檔案/etc/centos-release中每個單詞（由字母組成）顯示在獨立一行，並無空行
[root@localhost ~]# cat /etc/centos-release|tr -d '\n'| tr ' ' '\n'
CentOS
Linux
release
7.6.1810
(Core)