Linux

• 内存管理
  • 内存释放
    • drop_caches
• GUI
  • X11
• tmux
  • 遇到过的问题
• Shell
  • 遇到过的问题
• 修订记录

内存管理

内存释放

drop_caches

drop_caches

Writing to this will cause the kernel to drop clean caches, as well as

reclaimable slab objects like dentries and inodes. Once dropped, their

memory becomes free.

To free pagecache:

echo 1 > /proc/sys/vm/drop_caches

To free reclaimable slab objects (includes dentries and inodes):

echo 2 > /proc/sys/vm/drop_caches

To free slab objects and pagecache:

echo 3 > /proc/sys/vm/drop_caches

This is a non-destructive operation and will not free any dirty objects.

To increase the number of objects freed by this operation, the user may run

`sync’ prior to writing to /proc/sys/vm/drop_caches. This will minimize the

number of dirty objects on the system and create more candidates to be

dropped.

This file is not a means to control the growth of the various kernel caches

(inodes, dentries, pagecache, etc…) These objects are automatically

reclaimed by the kernel when memory is needed elsewhere on the system.

Use of this file can cause performance problems. Since it discards cached

objects, it may cost a significant amount of I/O and CPU to recreate the

dropped objects, especially if they were under heavy use. Because of this,

use outside of a testing or debugging environment is not recommended.

You may see informational messages in your kernel log when this file is

used:

cat (1234): drop_caches: 3

These are informational only. They do not mean that anything is wrong

with your system. To disable them, echo 4 (bit 3) into drop_caches.

——引用自https://www.kernel.org/doc/Documentation/sysctl/vm.txt

GUI

X11

Configure X11 Forwarding with PuTTY and Xming - CentLinux

tmux

遇到过的问题

Is there any way to redraw tmux window when switching smaller monitor to bigger one? - Stack Overflow

Shell

遇到过的问题

• command line - Linux tools to treat files as sets and perform set operations on them - Unix & Linux Stack Exchange

• linux - Shell command to monitor changes in a file - Server Fault：tail -F

• bash - Select unique or distinct values from a list in UNIX shell script - Stack Overflow：uniq -u

• string - How to trim whitespace from a Bash variable? - Stack Overflow

• bash - Check if string is neither empty nor space in shell script - Stack Overflow

• linux - Print a file, skipping the first X lines, in Bash - Stack Overflow

• bash - How to get the start time of a long-running Linux process? - Stack Overflow

• bash - Is it possible to make writing to .bash_history immediate? - Ask Ubuntu

修订记录

修订时间	修订人	版本	说明
TODO	wsxq2	1.0	初稿

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