PATH environment variables are also cached.

The PATH Environment Variable also has the cache hash-hash database access methodhase command: used to display and clear the hash table. When executing the command, the system first queries the hash table. When you enter a command, you first search for it in the hash table. If it does not exist, you can use the PATH specified by the $ PATH environment variable to find the command and then execute it. At the same time, it will also be placed in the hash table, and the current time when the same command is executed, it will not be searched through $ PATH. To improve the efficiency of command execution. Display the command usage frequency in the hash table $ hashhits command 6/usr/bin/svn 1/bin/chown 3/bin/bash 4/usr/bin/git 12/usr/bin/php 1/bin/rm 1/bin/chmod 1/usr/bin/nmap 5/bin/cat 13/usr/bin/vim 3/usr/bin/sudo 4/bin/ sed 2/bin/ps 2/usr/bin/man 23/bin/ls display hash table $ hash-lbuiltin hash-p/usr/bin/svn svnbuiltin hash-p/bin /chown chownbuiltin hash-p/bin/bash bashbuiltin hash-p/usr/bin/git gitbuiltin hash-p/usr/bin/php phpbuiltin hash-p/bin/rm rmbuiltin hash -p/bin/chmod chmodbuiltin hash-p/usr/bin/nmap nmapbuiltin hash-p/bin/cat catbuiltin hash-p/usr/bin/vim vimbuiltin hash-p/usr /bin/sudo sudobuiltin hash-p/bin/sed sedbuiltin hash-p/bin/ps psbuiltin hash-p/usr/bin/man manbuiltin hash-p/bin/ls display full command path $ hash-t git/usr/bin/git add content to the hash table $ hash-p/home/www/deployment/run $ runUsage: /home/www/deployment/run [OPTION] <server-id> <directory/timepoint> OPTION: development <domain>