Use environment variables in crontab (you can manually execute shell scripts, but not in scheduled tasks)

How to reference defined environment variables in crontab
A shell script/root/test/Shell/test_crontab_env.sh uses an environment variable test_crontab_env = test_crontab_env.
Test_crontab_env exists in/etc/profile.
For example:
#! /Bin/bash
Echo "'date + % Y-% m-% d" "% H: % m: % s' $ test_crontab_env">/tmp/test_crontab_env.file
Run the command manually. The running result is as follows:
2010-09-04 11:23:38 test_crontab_env
Add to crontab as follows
*/1 *****/root/test/Shell/test_crontab_env.sh
Result:
$> CAT/tmp/test_crontab_env.file
2010-09-04 11:25:01
2010-09-04 11:26:01
...
The environment variable referenced here is invalid.

How to Make environment variables take effect in crontab:
1. Method of passing Parameters
Crontab
*/1 *****/root/test/Shell/test_crontab_env.sh "test_crontab_env"
Test_crontab_env.sh
#! /Bin/bash
Echo "'date + % Y-% m-% d" "% H: % m: % s' $1">/tmp/test_crontab_env.file
2. Define environment variables in the shell script
Test_crontab_env.sh
#! /Bin/bash
Test_crontab_env = test_crontab_env
Echo "'date + % Y-% m-% d" "% H: % m: % s' $ test_crontab_env">/tmp/test_crontab_env.file
3. Load the environment variable file in the shell script
#! /Bin/bash
Source/etc/profile
Echo "'date + % Y-% m-% d" "% H: % m: % s' $ test_crontab_env">/tmp/test_crontab_env.file

I personally think the third method is the most practical.