$ ac –d
Dec 1 total 1.08
Dec 2 total 0.99
Dec 3 total 3.39
Dec 4 total 4.50
Today total 6.10
$ ac -p
john 3.64
madison 0.06
sanjay 88.17
nisha 105.92
ramesh 111.42
total 309.21
$ ac -d sanjay
Jul 2 total 12.85
Aug 25 total 5.05
Sep 3 total 1.03
Sep 4 total 5.37
Dec 24 total 8.15
Dec 29 total 1.42
Today total 2.95
语法: diff [选项] file1 file2
# diff -w name_list.txt name_list_new.txt
2c2,3
< John Doe
---
> John M Doe
> Jason Bourne
$ stat /etc/my.cnf
File: `/etc/my.cnf'
Size: 346 Blocks: 16 IO Block: 4096 regular file
Device: 801h/2049d Inode: 279856 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid:
( 0/ root)
Access: 2009-01-01 02:58:30.000000000 -0800
Modify: 2006-06-01 20:42:27.000000000 -0700
Change: 2007-02-02 14:17:27.000000000 -0800
$ stat /home/ramesh
File: `/home/ramesh'
Size: 4096 Blocks: 8 IO Block:
4096 directory
Device: 803h/2051d Inode: 5521409 Links: 7
Access: (0755/drwxr-xr-x) Uid: ( 401/ramesh) Gid: (
401/ramesh)
Access: 2009-01-01 12:17:42.000000000 -0800
Modify: 2009-01-01 12:07:33.000000000 -0800
Change: 2009-01-09 12:07:33.000000000 -0800
$ stat -f /
File: "/"
ID: 0 Namelen: 255 Type: ext2/ext3
Blocks: Total: 2579457 Free: 2008027 Available:
1876998 Size: 4096
Inodes: Total: 1310720 Free: 1215892
cut -d: -f 1 names.txt
Emma Thomas
Alex Jason
Madison Randy
Sanjay Gupta
Nisha Singh
cut -d: -f 1,3 names.txt
Emma Thomas:Marketing
Alex Jason:Sales
Madison Randy:Product Development
Sanjay Gupta:Support
Nisha Singh:Sales
cut -c 1-8 names.txt
Emma Tho
Alex Jas
Madison
Sanjay G
Nisha Si
$ sort namesd.txt | uniq
$ sort –u namesd.txt
$ sort namesd.txt | uniq –c
2 Alex Jason:200:Sales
2 Emma Thomas:100:Marketing
1 Madison Randy:300:Product Development
1 Nisha Singh:500:Sales
1 Sanjay Gupta:400:Support
$ sort namesd.txt | uniq –cd
2 Alex Jason:200:Sales
2 Emma Thomas:100:Marketing
employee_name:employee_id:department_name.
cat names.txt
Emma Thomas:100:Marketing
Alex Jason:200:Sales
Madison Randy:300:Product Development
Sanjay Gupta:400:Support
Nisha Singh:500:Sales
sort names.txt
Alex Jason:200:Sales
Emma Thomas:100:Marketing
Madison Randy:300:Product Development
Nisha Singh:500:Sales
Sanjay Gupta:400:Support
sort -r names.txt
Sanjay Gupta:400:Support
Nisha Singh:500:Sales
Madison Randy:300:Product Development
Emma Thomas:100:Marketing
Alex Jason:200:Sales
sort -t: -k 2 names.txt
Emma Thomas:100:Marketing
Alex Jason:200:Sales
Madison Randy:300:Product Development
Sanjay Gupta:400:Support
Nisha Singh:500:Sales
sort -t: -u -k 3 names.txt
Emma Thomas:100:Marketing
Madison Randy:300:Product Development
Alex Jason:200:Sales
Sanjay Gupta:400:Support
sort -t: -k 3n /etc/passwd | more
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n /etc/hosts
127.0.0.1 localhost.localdomain localhost
192.168.100.101 dev-db.thegeekstuff.com dev-db
192.168.100.102 prod-db.thegeekstuff.com prod-db
192.168.101.20 dev-web.thegeekstuff.com dev-web
192.168.101.21 prod-web.thegeekstuff.com prod-web
# find /etc -name "*.conf" | xargs ls –l
# cat url-list.txt | xargs wget –c
# find / -name *.jpg -type f -print | xargs tar -cvzf
images.tar.gz
# ls *.jpg | xargs -n1 -i cp {} /external-hard-
drive/directory
cat employee.txt
100 Jason Smith
200 John Doe
300 Sanjay Gupta
400 Ashok Sharma
tr a-z A-Z < employee.txt
100 JASON SMITH
200 JOHN DOE
300 SANJAY GUPTA
400 ASHOK SHARMA
cat department.txt
100 FINANCE
200 MARKETING
300 PRODUCT DEVELOPMENT
400 SALES
tr A-Z a-z < department.txt
100 finance
200 marketing
300 product development
400 sales
cat employee.txt
100 Jason Smith
200 John Doe
300 Sanjay Gupta
400 Ashok Sharma
cat bonus.txt
100 $5,000
200 $500
300 $3,000
400 $1,250
# join employee.txt bonus.txt
100 Jason Smith $5,000
200 John Doe $500
300 Sanjay Gupta $3,000
400 Ashok Sharma $1,250
# cat file.txt > /dev/null
# ./shell-script.sh > /dev/null
# cat invalid-file-name.txt 2> /dev/null
# ./shell-script.sh 2> /dev/null
语法: find [pathnames] [conditions]
# find /etc -name "*mail*"
# find / -type f -size +100M
# find . -mtime +60
# find . –mtime -2
# find / -type f -name *.tar.gz -size +100M -exec ls -l {} \;
# find / -type f -name *.tar.gz -size +100M -exec rm -f {} \;
Syntax: grep [options] pattern [files]
# grep John /etc/passwd如果给这个命令加上-v 参数将显示除了匹配行以外的其他行,下面的例子中将查找/etc/passwod文件中所有不包含John字符串的行。注意，在这个文件中有很多行都不匹配这个文本我们这里只显示了第一行：
jsmith:x:1082:1082:John Smith:/home/jsmith:/bin/bash
jdoe:x:1083:1083:John Doe:/home/jdoe:/bin/bash
# grep -v John /etc/passwd查找文件中有多少行匹配某个特定的文本
jbourne:x:1084:1084:Jason Bourne:/home/jbourne:/bin/bash
# grep -c John /etc/passwd
2
# grep -cv John /etc/passwd
39
# grep -i john /etc/passwd
jsmith:x:1082:1082:John Smith:/home/jsmith:/bin/bash
jdoe:x:1083:1083:John Doe:/home/jdoe:/bin/bash
# grep -ri john /home/users
/home/users/subdir1/letter.txt:John, Thanks for your
contribution.
/home/users/name_list.txt:John Smith
/home/users/name_list.txt:John Doe
# grep -ril john /root
/home/users/subdir1/letter.txt
/home/users/name_list.txt
localhost ssh -l jsmith remotehost
remotehost [注意: ~s 是不会再你的命令行上显示的]
remote host: remotehost
local host: localhost
remote version: SSH-1.99-OpenSSH_3.9p1
local version: SSH-2.0-3.2.9.1 SSH Secure
Shell (non-commercial)
compressed bytes in: 1506
uncompressed bytes in: 1622
compressed bytes out: 4997
uncompressed bytes out: 5118
packets in: 15
packets out: 24
rekeys: 0
Algorithms:
Chosen key exchange algorithm: diffie-hellman-
group1-sha1
Chosen host key algorithm: ssh-dss
Common host key algorithms: ssh-dss,ssh-rsa
Algorithms client to server:
Cipher: aes128-cbc
MAC: hmac-sha1
Compression: zlib
Algorithms server to client:
Cipher: aes128-cbc
MAC: hmac-sha1
Compression: zlib
localhost$
localhost$ ssh -l jsmith remotehost
remotehost$
remotehost$ ~^Z
[1]+ Stopped ssh -l jsmith remotehost
localhost$
localhost$ jobs
[1]+ Stopped ssh -l jsmith remotehost
localhost$ fg %1
ssh -l jsmith remotehost
remotehost$
localhost$ ssh -l jsmith remotehost.example.com
warning: Connecting to remotehost.example.com failed:
No address associated to the name
locaclhost$ ssh -v -l jsmith remotehost.example.com
debug:
SshConfig/sshconfig.c:2838/ssh2_parse_config_ext:
Metaconfig parsing stopped at line 3.
debug:
SshConfig/sshconfig.c:637/ssh_config_set_param_verbose:
Setting variable 'VerboseMode’ to 'FALSE’.
debug:
SshConfig/sshconfig.c:3130/ssh_config_read_file_ext:
Read 17 params from config file.
debug: Ssh2/ssh2.c:1707/main: User config file not
found, using defaults. (Looked for
'/home/jsmith/.ssh2/ssh2_config’)
debug: Connecting to remotehost.example.com, port 22…
(SOCKS not used)
warning: Connecting to remotehost.example.com failed:
No address associated to the name
localhost ssh -l jsmith remotehost.example.com
Host key not found from database.
Key fingerprint:
xabie-dezbc-manud-bartd-satsy-limit-nexiu-jambl-title-jarde-
tuxum
You can get a public key’s fingerprint by running
% ssh-keygen -F publickey.pub
on the keyfile.
Are you sure you want to continue connecting (yes/no)? Yes
Host key saved to
/home/jsmith/.ssh2/hostkeys/key_22_remotehost.example.com.pu
host key for remotehost.example.com, accepted by jsmith Mon
May 26 2008 16:06:50 -0700
jsmith@remotehost.example.com password:
remotehost.example.com$
localhost ssh -l jsmith remotehost.example.com
jsmith@remotehost.example.com password:
remotehost.example.com$
localhost ssh -l jsmith remotehost.example.com @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the- middle attack)! It is also possible that the host key has just been changed. Please contact your system administrator. Add correct host key to “/home/jsmith/.ssh2/hostkeys/key_22_remotehost.example.com.pu b” to get rid of this message. Received server key’s fingerprint: xabie-dezbc-manud-bartd-satsy-limit-nexiu-jambl-title-arde- tuxum You can get a public key’s fingerprint by running % ssh-keygen -F publickey.pub on the keyfile. Agent forwarding is disabled to avoid attacks by corrupted servers. Are you sure you want to continue connecting (yes/no)? yes Do you want to change the host key on disk (yes/no)? yes Agent forwarding re-enabled. Host key saved to /home/jsmith/.ssh2/hostkeys/key_22_remotehost.example.com.pub host key for remotehost.example.com, accepted by jsmith Mon May 26 2008 16:17:31 -0700 jsmith @remotehost.example.com’s password: remotehost$
<database>
<table name='product'>
<field name='P_name' type='string'/>
<field name='P_brand' type='string'/>
<field name='P_price' type='number'/>
<field name='P_unit' type='string'/>
</table>
<table name='part'>
<field name='P_name' type='string'/>
<field name='P_platform' type='string'/>
<field name='P_weight' type='number'/>
<field name='P_volume' type='number'/>
</table>
</database>
from xml.dom.minidom import parse
import re
dom=parse("config.xml")
for table in dom.getElementsByTagName('table'):
tableName=field.getAttributeNode('name').nodeValue
for field in field.getElementsByTagName('field'):
name=style.getAttributeNode('name').nodeValue
type=style.getAttributeNode('type').nodeValue
if re.search('p_name',name):
print tableName,',',name,',',type
ssh -V
OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
下面命令显示这个操作系统使用的是SSH2的客户端：
$ ssh -V
ssh: SSH Secure Shell 3.2.9.1 (non-commercial version)
on i686-pc-linux-gnu
$ date
Thu Jan 1 08:30:07 PST 2009
$ date --date='3 seconds'
Thu Jan 1 08:30:12 PST 2009
$ date --date='4 hours'
Thu Jan 1 12:30:17 PST 2009
$ date --date='tomorrow'
Fri Jan 2 08:30:25 PST 2009
$ date --date="1 day"
Fri Jan 2 08:30:31 PST 2009
$ date --date="1 days"
Fri Jan 2 08:30:38 PST 2009
$ date --date="2 days"
Sat Jan 3 08:30:43 PST 2009
$ date --date='1 month'
Sun Feb 1 08:30:48 PST 2009
$ date --date='1 week'
Thu Jan 8 08:30:53 PST 2009
$ date --date="2 months"
Sun Mar 1 08:30:58 PST 2009
$ date --date="2 years"
Sat Jan 1 08:31:03 PST 2011
$ date --date="next day"
Fri Jan 2 08:31:10 PST 2009
$ date --date="-1 days ago"
Fri Jan 2 08:31:15 PST 2009
$ date --date="this Wednesday"
Wed Jan 7 00:00:00 PST 2009
$ date --date='3 seconds ago'
Thu Jan 1 08:27:00 PST 2009
$ date --date="1 day ago"
Wed Dec 31 08:27:13 PST 2008
$ date --date="1 days ago"
Wed Dec 31 08:27:18 PST 2008
$ date --date="1 month ago"
Mon Dec 1 08:27:23 PST 2008
$ date --date="1 year ago"
Tue Jan 1 08:27:28 PST 2008
$ date --date="yesterday"
Wed Dec 31 08:27:34 PST 2008
$ date --date="10 months 2 day ago"
Thu Feb 28 08:27:41 PST 2008
date
Thu Jan 1 08:19:23 PST 2009
date --date="now"
Thu Jan 1 08:20:05 PST 2009
date --date="today"
Thu Jan 1 08:20:12 PST 2009
date --date='1970-01-01 00:00:01 UTC +5 hours' +%s
18001
date '+Current Date: %m/%d/%y%nCurrent Time:%H:%M:%S'
Current Date: 01/01/09
Current Time:08:21:41
date +"%d-%m-%Y"
01-01-2009
date +"%d/%m/%Y"
01/01/2009
date +"%A,%B %d %Y"
Thursday,January 01 2009
# hwclock –systohc
# hwclock --systohc –utc
# hwclock
# cat /etc/sysconfig/clock
ZONE="America/Los_Angeles"
UTC=false
ARC=false
# date {mmddhhmiyyyy.ss}# date 013122192009.53
# date 013122192009.53
# date +%Y%m%d -s "20090131"
# date -s "01/31/2009 22:19:53"
# date -s "31 JAN 2009 22:19:53"
# date set="31 JAN 2009 22:19:53"
# date +%T -s "22:19:53"
# date +%T%p -s "10:19:53PM"
# cd /etc/mall
-bash: cd: /etc/mall: No such file or directory
# shopt -s cdspell
# cd /etc/mall
# pwd
/etc/mail
[注意：由于拼写错误，我把mail写成了mall，这里cd自动更正了这个错误。]
# popd
-bash: popd: directory stack empty
# dirs
~
# pwd
/home/ramesh
# mkdir /tmp/dir1
# mkdir /tmp/dir2
# mkdir /tmp/dir3
# mkdir /tmp/dir4
# cd /tmp/dir1
# pushd .
# cd /tmp/dir2
# pushd .
# cd /tmp/dir3
# pushd .
# cd /tmp/dir4
# pushd .
# dirs
/tmp/dir4 /tmp/dir4 /tmp/dir3 /tmp/dir2 /tmp/dir1
[注意：这里的的第一个目录 (/tmp/dir4) 永远是当前的目录]
/tmp/dir4
/tmp/dir3
/tmp/dir2
/tmp/dir1
# popd
# pwd
/tmp/dir4
[注意:执行上面的命令后，目录堆栈中的内容为：
/tmp/dir3
/tmp/dir2
/tmp/dir1]
# popd
# pwd
/tmp/dir3
[注意:执行上面的命令后，目录堆栈中的内容为：
/tmp/dir2
/tmp/dir1]
# popd
# pwd
/tmp/dir2
[注意:执行上面的命令后，目录堆栈中的内容为：
/tmp/dir1]
# popd
# pwd
/tmp/dir1
[注意:执行上面的命令后，目录堆栈中的内容为空]
# popd
-bash: popd: directory stack empty
# cd /tmp/subdir1/subdir2/subdir3
# cd -
# pwd
/tmp/very/long/directory/structure/that/is/too/deep
# cd -
# pwd
/tmp/subdir1/subdir2/subdir3
# cd -
# pwd
/tmp/very/long/directory/structure/that/is/too/deep
# mkdir -p /tmp/subdir1/subdir2/subdir3
# cd /tmp/subdir1/subdir2/subdir3
# pwd
/tmp/subdir1/subdir2/subdir3
vi .bash_profile
function mkdircd () { mkdir -p "$@" && eval cd
"\"\$$#\""; }
# mkdircd /tmp/subdir1/subdir2/subdir3
[注意：现在你可以在创建一个目录后自动导航到这个目录下]
# pwd
/tmp/subdir1/subdir2/subdir3
# mkdir -p除了使用cd ../../../.. 命令导航到当前目录上面四层的目录，你还可以使用以下之一的方法：
/tmp/very/long/directory/structure/that/is/too/deep
# cd /tmp/very/long/directory/structure/that/is/too/deep
# pwd
/tmp/very/long/directory/structure/that/is/too/deep
# cd ../../../../
# pwd
/tmp/very/long/directory/structure
alias ..="cd .."
alias ..2="cd ../.."
alias ..3="cd ../../.."
alias ..4="cd ../../../.."
alias ..5="cd ../../../../.."
# cd
/tmp/very/long/directory/structure/that/is/too/deep
# ..4
[注意我们这里使用..4来导航到上面四层目录中]
# pwd
/tmp/very/long/directory/structure/
alias ..="cd .."
alias ...="cd ../.."
alias ....="cd ../../.."
alias .....="cd ../../../.."
alias ......="cd ../../../../.."
# cd /tmp/very/long/directory/structure/that/is/too/deep
# .....
[注意：我们这里使用了.....(五个点号)向上导航了4层目录]
# pwd
/tmp/very/long/directory/structure/
alias cd..="cd .."
alias cd...="cd ../.."
alias cd....="cd ../../.."
alias cd.....="cd ../../../.."
alias cd......="cd ../../../../.."
# cd /tmp/very/long/directory/structure/that/is/too/deep
# cd.....
[注意：这里使用cd.....导航到上四层目录]
# pwd
/tmp/very/long/directory/structure
alias cd1="cd .."
alias cd2="cd ../.."
alias cd3="cd ../../.."
alias cd4="cd ../../../.."
alias cd5="cd ../../../../.."
[ramesh@dev-db ~]# pwd
/home/ramesh
[ramesh@dev-db ~]# cd mail
-bash: cd: mail: No such file or directory
[注意：上面的命令是在当前路径下查找mail子目录]
[ramesh@dev-db ~]# export CDPATH=/etc
[ramesh@dev-db ~]# cd mail
/etc/mail
[注意：现在我们查找的是etc目录下的mail子目录]
[ramesh@dev-db /etc/mail]# pwd
/etc/mail
export CDPATH=.:~:/etc:/var这一技巧在下列情况中非常有用: