Reference
- http://blog.jobbole.com/86948/ : 11个让你吃惊的 Linux 终端命令
- http://coolshell.cn/articles/8883.html : 应该知道的Linux技巧(from coolshell)
- http://coolshell.cn/articles/4990.html : 程序员技术练级攻略
- http://linuxtools-rst.readthedocs.org/zh_CN/latest/index.html : Linux工具快速教程(complete)
Bash Shell Shortcut
- 在 bash 里，使用 Ctrl-R 而不是上下光标键来查找历史命令。
- 在 bash里，使用 Ctrl-W 来删除最后一个单词，使用 Ctrl-U 来删除一行。请man bash后查找Readline Key Bindings一节来看看bash的默认热键，比如：Alt-. 把上一次命令的最后一个参数打出来，而Alt-* 则列出你可以输入的命令。
System Directory Structure
- /bin : All the executable binary programs (file) required during booting, repairing, files required to run into single-user-mode, and other important, basic commands 需要在[单用户模式]可用的必要命令（[可执行文件]）；面向所有用户，例如：cat, ls, cp.
- /boot : Holds important files during boot-up process, including Linux Kernel.
- /dev : Contains device files for all the hardware devices on the machine e.g., cdrom, cpu, etc
- /etc : Contains Application’s configuration files, startup, shutdown, start, stop script for every individual program.
- /home : Home directory of the users. Every time a new user is created, a directory in the name of user is created within home directory which contains other directories. For Mac, user files are stored in Users.
- /lib : The Lib directory contains kernel modules and shared library images required to boot the system and run commands in root file system.
- /media : Temporary mount directory is created for removable devices viz., media/cdrom.
- /mnt : Temporary mount directory for mounting file system.
- /opt : Optional is abbreviated as opt. Contains third party application software. Viz., Java, etc.
- /proc : A virtual and pseudo file-system which contains information about running process with a particular Process-id aka pid.
- /root : This is the home directory of root user and should never be confused with ‘/‘
- /run : This directory is the only clean solution for early-runtime-dir problem.
- /sbin : Contains binary executable programs, required by System Administrator, for Maintenance. 必要的系统二进制文件，例如： init、 ip、 mount。
- /srv : Service is abbreviated as ‘srv‘. This directory contains server specific and service related files.
- /sys : Modern Linux distributions include a /sys directory as a virtual filesystem, which stores and allows modification of the devices connected to the system.
- /tmp :System’s Temporary Directory, Accessible by users and root. Stores temporary files for user andsystem, till next boot.
- /usr : Contains executable binaries, documentation, source code, libraries for second level program.
- /var : Stands for variable. The contents of this file is expected to grow. This directory contains log, lock,spool, mail and temp files.
Some further explanation
bin is different from lib. bin is for binary file, while lib or Library is for library (like dynamic/static linking library).
-
/usr – User Programs
Contains binaries, libraries, documentation, and source-code for second level programs.- /usr/bin contains binary files for user programs. If you can’t find a user binary under /bin, look under /usr/bin. For example: at, awk, cc, less, scp. 非必要可执行文件(在单用户模式中不需要)；面向所有用户。
- /usr/sbin contains binary files for system administrators. If you can’t find a system binary under /sbin, look under /usr/sbin. For example: atd, cron, sshd, useradd, userdel. 非必要的系统二进制文件，例如：大量[网络服务]的[守护进程]。
- /usr/lib contains libraries for /usr/bin and /usr/sbin
- /usr/local contains users programs that you install from source. For example, when you install apache from source, it goes under /usr/local/apache2. 本地数据的第三层次， 具体到本台主机。通常而言有进一步的子目录， 例如：bin/, lib/, share/.
/lib – System Libraries
Contains library files that supports the binaries located under /bin and /sbin
Library filenames are either ld* or lib.so.
For example: ld-2.11.1.so, libncurses.so.5.7/etc – Configuration Files
Contains configuration files required by all programs.
This also contains startup and shutdown shell scripts used to start/stop individual programs.
For example: /etc/resolv.conf, /etc/logrotate.conf/bin – User Binaries
Contains binary executables.
Common linux commands you need to use in single-user modes are located under this directory.
Commands used by all the users of the system are located here.
For example: ps, ls, ping, grep, cp./sbin – System Binaries
Just like /bin, /sbin also contains binary executables.
But, the linux commands located under this directory are used typically by system aministrator, for system maintenance purpose.
For example: iptables, reboot, fdisk, ifconfig, swapon/etc/ssh/
Other important directories under user directory:
- /Users/abrocod/.ssh
- /Users/abrocod/.aws
Common Shell Command
Simple Command Collection
- which
- whereis
- whoami
- date
- printenv
- env
- alias
alias ls='ls --color=auto'
alias grep='grep --color=auto'
sudo -i # run as root user
sudo !!
sudo -E
ls
-l ：列出长数据串，包含文件的属性与权限数据等
-a ：列出全部的文件，连同隐藏文件（开头为.的文件）一起列出来（常用）
-d ：仅列出目录本身，而不是列出目录的文件数据
-h ：将文件容量以较易读的方式（GB，kB等）列出来
-R ：连同子目录的内容一起列出（递归列出），等于该目录下的所有文件都会显示出来
du, df
check directory size and check the whole disk space utility
du -sh
du -h
df -h
grep
grep [-acinv] [--color=auto] '查找字符串' filename
-a ：将binary文件以text文件的方式查找数据
-c ：计算找到‘查找字符串’的次数
-i ：忽略大小写的区别，即把大小写视为相同
-v ：反向选择，即显示出没有‘查找字符串’内容的那一行
------- 例如：-------
取出文件/etc/man.config中包含MANPATH的行，并把找到的关键字加上颜色:
grep --color=auto 'MANPATH' /etc/man.config
把ls -l的输出中包含字母file（不区分大小写）的内容输出:
ls -l | grep -i file
- search for pattern
grep "pattern" -r *
cut
clean file:
cut -c3-73 sample_thumbid.txt > clean_tbnail.txt
find
find [PATH] [option] [action]
与时间有关的参数：
-mtime n : n为数字，意思为在n天之前的“一天内”被更改过的文件；
-mtime +n : 列出在n天之前（不含n天本身）被更改过的文件名；
-mtime -n : 列出在n天之内（含n天本身）被更改过的文件名；
-newer file : 列出比file还要新的文件名
例如：
find /root -mtime 0 # 在当前目录下查找今天之内有改动的文件
与用户或用户组名有关的参数：
-user name : 列出文件所有者为name的文件
-group name : 列出文件所属用户组为name的文件
-uid n : 列出文件所有者为用户ID为n的文件
-gid n : 列出文件所属用户组为用户组ID为n的文件
例如：
find /home/ljianhui -user ljianhui # 在目录/home/ljianhui中找出所有者为ljianhui的文件
与文件权限及名称有关的参数：
-name filename ：找出文件名为filename的文件
-size [+-]SIZE ：找出比SIZE还要大（+）或小（-）的文件
-tpye TYPE ：查找文件的类型为TYPE的文件，TYPE的值主要有：一般文件（f)、设备文件（b、c）、
目录（d）、连接文件（l）、socket（s）、FIFO管道文件（p）；
-perm mode ：查找文件权限刚好等于mode的文件，mode用数字表示，如0755；
-perm -mode ：查找文件权限必须要全部包括mode权限的文件，mode用数字表示
-perm +mode ：查找文件权限包含任一mode的权限的文件，mode用数字表示
例如：
find / -name passwd # 查找文件名为passwd的文件
find ./ -name '.o'
find ./ -name ".o" -exec rm {} ;
find . -perm 0755 # 查找当前目录中文件权限的0755的文件
find . -size +12k # 查找当前目录中大于12KB的文件，注意c表示byte
cp
-a ：将文件的特性一起复制
-p ：连同文件的属性一起复制，而非使用默认方式，与-a相似，常用于备份
-i ：若目标文件已经存在时，在覆盖时会先询问操作的进行
-r ：递归持续复制，用于目录的复制行为
-u ：目标文件与源文件有差异时才会复制
cp -a file1 file2 #连同文件的所有特性把文件file1复制成文件file2
cp file1 file2 file3 dir #把文件file1、file2、file3复制到目录dir中
mv
-f ：force强制的意思，如果目标文件已经存在，不会询问而直接覆盖
-i ：若目标文件已经存在，就会询问是否覆盖
-u ：若目标文件已经存在，且比目标文件新，才会更新
mv file1 file2 file3 dir # 把文件file1、file2、file3移动到目录dir中
mv file1 file2 # 把文件file1重命名为file2
rm
-f ：就是force的意思，忽略不存在的文件，不会出现警告消息
-i ：互动模式，在删除前会询问用户是否操作
-r ：递归删除，最常用于目录删除，它是一个非常危险的参数
rm -i file # 删除文件file，在删除之前会询问是否进行该操作
rm -fr dir # 强制删除目录dir中的所有文件
file
file filename
例如：
file ./test
tar
-c ：新建打包文件
-t ：查看打包文件的内容含有哪些文件名
-x ：解打包或解压缩的功能，可以搭配-C（大写）指定解压的目录，注意-c,-t,-x不能同时出现在同一条命令中
-j ：通过bzip2的支持进行压缩/解压缩
-z ：通过gzip的支持进行压缩/解压缩
-v ：在压缩/解压缩过程中，将正在处理的文件名显示出来
-f filename ：filename为要处理的文件
-C dir ：指定压缩/解压缩的目录dir
压缩：tar -zcvf filename.tar.gz 要被处理的文件或目录名称
查询：tar -ztvf filename.tar.gz
解压：tar -zxvf filename.tar.gz -C 欲解压缩的目录
tar -zcvf test.tar.gz *
Note: -f option must follow the filename !!!
-- if the file is just .tar, not .tar.gz or .tar.bz2, then use:
tar -xvf filename.tar -C ./dir
-- if the file is just a .zip
unzip file.zip -d destination_folder
zip
zip squash.zip file1 file2 file3
zip -r squash.zip dir1 # zip recursively, -r
unzip squash.zip
use less squash.zip to look at the content of zip file
or use 'unzip -l squash.zip', which is the same as less
ln
ln cc ccAgain :硬连接；删除一个，将仍能找到；
ln -s cc ccTo :符号链接(软链接)；删除源，另一个无法使用；（后面一个ccTo 为新建的文件）
ln -s TARGET LINK_NAME
- Find the link after softlink
ls -l `which java`
lrwxr-xr-x 1 root wheel 74 Sep 1 15:27 /usr/bin/java -> /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java
chgrp, chown
chgrp [-R] dirname/filename
-R ：进行递归的持续对所有文件和子目录更改
例如：
chgrp users -R ./dir # 递归地把dir目录下中的所有文件和子目录下所有文件的用户组修改为users
groups
-- chown
chown owner-user file
chown owner-user:owner-group file
chown owner-user:owner-group directory
chown options owner-user:owner-group file
e.g:
chown vivek demo.txt # change owner
chown vivek:vivek demo.txt # change owner and group
chown :ftp demo.txt # change only group
chown -R vivek /home/vivek # recursively change
open file in Ubuntu
You can use:
gnome-open file2open.xxx (xxx = some file extension).
With this command gnome will invoke the default app for "xxx"
----------- for example evince if you want to open pdf ------------
Or specifically:
evince file2open.pdf
Or (default for KDE):
okular file2open.pdf
process management
ps
ps [aux]
ps aux | grep 'chrome' | less
pstree
top
Top will give you a realtime view of the system and only show the number of processes which will fit on the screen.
kill
kill [signal]
e.g:
kill 6978
kill -1 6978 // kill/quit the process gently
kill -9 6978 // kill the process with brutal force
lsof
If you know what port the process is running you can type: lsof -i:
tail
The command tail -f will display the last 10 lines of a file, and then continuously wait for new lines, and display them as they appear.
$ tail -f /var/log/messages
If you want to see more than ten lines at the outset, specify the new number (say 50 lines) like this:
$ tail -50 -f /var/log/messages