Linux 經常使用命令

Linux 經常使用命令收集

這篇筆記是筆者整理的一些簡單有用的 Linux 命令，供平時查閱。

文件權限與用戶權限

# change file mod
chmod +rwx file
chmod 777 file
# 數字模式是使用二進制計算出來的，三位分別表明 owner,group,others，4 - r, w - 2, x - 1，則 7 = 4 + 2 + 1 = rwx
chown -c root ./hello.txt # change owner to root
chgrp -c root ./hello.txt # change group to root
# change login shell:
chsh
# or edit /etc/passwd.
# get /etc/passwd file in cygwin system:
mkpasswd -c | sed -e 'sX/bashX/zshX' | tee -a /etc/passwd

文件查看與搜索

# 顯示文本文件，展現，查看文件開頭部分，查看文件尾
cat file | less
head file
tail file

# find [path] [expr]
find /var /usr -name "*.pdf" # use -iname to ignore A or a
find /var -name "*.pdf" -a "*.txt" # -a means and
find /var -name "*.pdf" -type d # d means dir
find /var -name "*.pdf" -size +100c # +100c means more than 100 chars.
find .name "*.sh" ­-type f ­-exec cat {} \; # run `cat` for all finded files.
find . -type f -mmin -10 # any file changed in passed 10 minute.
find . -ctime -10 # change time, by day. ctime = change time, mtime = modified time, atime = access time.
locale # like find, but much speeder becase of using a datebase(update once perday).

# Search bin file path in PATH
which progName
# Search bin file path in system
whereis progName
apropos # 尋找具備 XXX 功能的命令
type CMD # make sure where a cmd from, bash or exec.

文件、文件系統管理

ln source_file target_dir
# make soft link: 
ln -s source_file_or_dir target_dir

tar -cvf  to_filename form_dir # 自動識別後綴名壓縮
tar -tvf filename # 自動識別後綴名瀏覽文件內容
tar -xvf filename # 自動識別後綴名解壓
# tar 其餘選項: c：建立，x：解壓，t：查看

# !!! Very useful !!!
# also work on mac
# check finder's disk usage
du -sh ./*

用戶管理

userdel username
useradd username
groupadd groupname
groupdel groupname

進程管理

ps # list all process 
top # an interact program to manage process
lsof # list opened files
kill 234 # kill a process by pid
nice # run a program with modified scheduling priority
renice # alter priority of running process

其餘

history # command history
id # my uid gid etc.
fsck.ext4 -p /dev/sdb1 # rapair EXT4 file system