CentOS Setup System Environment variables

1) The naïve practice of the first attempt:

Take the registered Golang environment variable as an example:

CD/ETC/PROFILE.D
Ls-rtl
Touch custom.sh # or any file name you like to create a new file
Ls-rtl
echo "E Xport Path=\${path}:/usr/local/go/bin "> custom.sh && chmod 755 custom.sh less
custom.sh
. custom.sh
Echo $PATH
reboot

It is not recommended to write directly to/etc/profile, but create a new shell script of your own, under the/ETC/PROFILE.D folder, which reads:

Export Path=${path}:/usr/local/go/bin

System startup automatically executes this script

For details, see the contents of the/etc/profile text:

#/etc/profile # System wide environment and startup programs, for login Setup # Functions and aliases Go IN/ETC/BASHRC # It's not a good the idea to the change of this file unless you know and is doing. It's much better to create a custom.sh shell script on #/etc/profile.d/to make custom changes to your environment, as th

is # would prevent the need for merging on future updates. Pathmunge () {    case ': ${path}: ' in         *: ' $ ':*)          
 ;         *)             IF ["$" = "after"];
Then                 path= $PATH: $             Else                 path=$1: $PATH             fi     ESAC} ... for i in/etc/profile.d/*.sh; do if [-R "$i"]; Then if ["${-#*i}"! = "$-"]; Then.
    "$i"    else. "$i" >/dev/null fi fi Done

$-represents the options for the current shell, see 1 2 3

echo "$-" shows the Himbh (5 options)

${-#*i} * Here is the string wildcard, #这里是字符串操作符, ${string#match_string}

Deletes shortest match of $match _string from front of $string. See 4

So ${-#*i} is MBH

However, after the above approach, there are two/usr/local/go/bin in the Echo $PATH in terminal. It's harmless, but it's strange that the script has been executed two times.

Yes, it was executed two times:

~/.BASHRC---/ETC/BASHRC also executed it again.

2) The appropriate practice:

Remove duplicates using the Pathmunge function defined in/etc/profile (/ETC/BASHRC):

echo "Pathmunge/usr/local/go/bin after" > custom.sh && chmod 755 custom.sh

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