lspci (| grep NVIDIA)
# 获取PCI连接的设备信息，如显卡、硬盘、显示器、无线网卡等外设

lsblk
# list block devices.
# 块设备即以block为单位进行数据读写的设备，
# 与character device相对

df -h (-T: show file system type)
# 显示mount到文件系统中的硬盘空间和分区的使用情况
df -i 
# 显示硬盘分区的节点使用情况

locate /path/to/locate/*opencv*
# 在/path/to/locate/文件夹中搜索路径名含有opencv的文件

find /path/to/find -name *opencv*
# 在/path/to/find/文件夹中搜索文件名含有opencv的文件

grep -ri 'pattern' /path/to/grep
# 在/path/to/grep/文件夹中recursively寻找pattern

sshpass -p "password" scp ...
# pass pwd to scp

ln -s src_file link_to_src_file
# create soft symbol link for src_file

tar -zcvf file.tar.gz file	# compress
tar -zxvf file.tar.gz (-C dst_dir)	# extract

md5sum file
# calculate MD5 hashes of file to verify file's integrity

du -sh /folder
# 统计文件夹大小

mount -t nfs (-o lookupcache=none) 192.168.0.1:/

command | tee out.txt
# redirect the stdout to file out.txt

#Xargs
find . -name '*.txt' | xargs -t ls -al  # -t means showing command, -p means typing 'y' to continue
find . -mtime +7 | xargs -I '{}' mv {} {}.backup    # backup files in the past week, {} represents the files

export PATH=$PATH:<path1>:<path2>
# 在环境变量$PATH末尾加多个path
export LD_LIBRARY_PATH=<path1>:<path2>:$LD_LIBRARY_PATH
# 在环境变量$LD_LIBRARY_PATH最前加多个path
# 常见环境变量有$JAVAHOME, $PYTHONPATH

ldconfig
# 系统的动态链接库会默认放在系统目录`/usr/lib`和`/lib`下，或者动态库配置文件`/etc/ld.so.conf`指定的非系统目录下，供应用程序共享。一般系统启动时会执行`ldconfig`命令对所有库文件建立索引。但是如果对链接库目录下的文件增删修改时（例如安装了新的包），就需要手动执行`ldconfig`以刷新索引。

ldconfig -v (| grep cuda)
# 扫描目录并显示搜索到的动态链接库

ldd
# Print shared library dependencies

pkg-config
# 每当安装一个软件时，系统会将一个描述软件的'.pc'文件放在$PKG_CONFIG_PATH中用来索引。

pkg-config --lib --cflags OpenEXR
-pthread -I/usr/include/OpenEXR -I/usr/include/libdrm  -pthread -lIlmImf -lImath -lHalf -lIex -lIexMath -lIlmThread

ps -aux | grep chrome
# Find all processes named chrome

kill -9 PID
# kill process

yum install sth
# One of the configured repositories failed (Unknown), and yum doesn't have enough cached data to continue.
# This issue mat occur due to corruption of the local machine cache, try to clear cache on system:
yum clean all
rm -r /var/cache/yum/*

# Screen
Ctrl+A then D # Detach from current screen
Ctrl+R or screen -R screen_id # Reenter screen
screen -ls # list running screens

# docker
docker ps	# list running containers
docker ps -a # list all containers

docker create --name=<container-name> -it <image-name/ID>
docker start <container-name/ID>	# start a existing container
docker stop <container-name/ID>	# stop a running container
docker exec -it <container-name/ID> bash	# log in the shell of a container
docker rm <container-name/ID> # remove a container