Operating Systems / Linux

You can set resources for all processes of the current user in the current shell . ulimit has soft limits and hard limits: Soft limit: any process can modify the soft limit, but the soft limit cannot exceed the hard limit. Hard limit: ordinary proces

1. Usage 1.1. Get the Network Interface Name tcpdump D ifconfig 1.2. Capture Packets Basic usage Advanced syntax Type keywords: host, port. Specify transmission direction: src, dst. Protocol keywords: tcp, udp. Logical operators: and, or. 1.3. Export

[toc] 1. Processes 1.1. top top 1.2. vmstat vmstat 1.3. ps ps 1.4. pstree pstree 1.5. ulimit ulimit 1.6. systemd systemd 1.7. pidstat pidstat 1.8. perf perf 2. Memory 2.1. free free 3. Disk 3.1. df df 3.2. iostat iostat 3.3. lsof lsof 3.4. strace str

1. Usage Output once per second. 2. Output 3. Explanation IFACE: network interface. rxpck/s: number of packets received per second. txpck/s: number of packets sent per second. rxkB/s: amount of data received per second, in KB. txkB/s: amount of data

Usage Output every 1 second. Output Explanation Time User ID Process PID Read throughput Write throughput

Usage View a process's system calls. Output

1. History of Linux Namespace Linux kernel version 2.4 supported mount namespace. Linux kernel version 2.6 supported most namespaces, such as IPC, Network, PID, and UTS. Linux kernel version 3.8 supported User namespace. 2. What Is Linux Namespace? l

1. History of Linux cgroup Google engineers developed process containers, which were later renamed control groups. Linux kernel version 2.6 supported cgroup. 2. What Is Linux cgroup? limits how much you can use A Linux kernel feature that limits proc

1. What Is chroot? A chroot in a Linux system is used to change the root directory. In a Linux system, the default directory structure begins with / ; chroot uses a specified location as the / location. 2. Why chroot Is Needed 2.1. Security Restrict

1. Install NeoVim 2. vim Shortcuts vim.md 3. References Neovim ArchWiki