Ubuntu utility commands (long-term updates)

1. Is the SO library 32bit or 64bit?

# 命令：
file [file_name]

# 示例：
file libboost_filesystem.so.1.66.0

# output:
libboost_filesystem.so.1.66.0: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), 
dynamically linked, BuildID[sha1]=a6fa9bd49328a82b8905b37aaebf651f809a0770, with debug_info, 
not stripped

2. Delete all content (files + folders) in the current directory

cd build 
rm -rf *

3. What do the different colors represent in Ubuntu?

Green: static library, dynamic library, executable
light blue: soft link

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Blue: folder
White: text file

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4. tar compression, decompression

tar -czvf xxx.tar.gz  source_file # 以tar.gz方式打包并gz方式压缩
tar -xzvf xxx.tar.gz -C path      # 解压缩包，path:解压目标路径

5. View Linux CPU frequency

// 当前频率
cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq 
816000

// 最大频率
cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq 
1800000

// 最小频率
cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq 
408000

6. Check the frequency of NPU (RK board)

cd /sys/class/devfreq

Enter this path, there is fde40000.npu (different boards may be different)

cat fde40000.npu/max_freq

7. Hard disk mount

Function: Mount the server hard disk to the Ubuntu directory via IP

sudo mount -t nfs IP:/volume1/SLAM/3Dfurniture /home/robot/Project/kxh-DM2/

8. Memory release

# 释放所有的显卡显存
fuser -vk /dev/nvidia*

# 释放指定PID的显卡显存
kill -9 PID(需要查找自己的PID)