4 ways to execute shell scripts in Linux summary

There are several ways to bash a shell script, assuming that the file name of the shell script we have written is hello.sh and that the file location is in the/data/shell directory and has execute permissions.

Method One: Switch to the directory where the shell script is located (at this time, called the working directory) to execute the shell script:

Copy CodeThe code is as follows: Cd/data/shell

./hello.sh

The./means to execute hello.sh under the current working directory. If you do not add./, bash may respond to an error message that cannot be found hello.sh. Because the current working directory (/data/shell) may not be the default search path for the executing program, that is, it is not in the contents of the environment variable pash. The Echo $PATH command is available to view the contents of the PATH. Now the/data/shell is not in the environment variable path, so you must add./To execute.

Method Two: Execute the Bash shell script in an absolute path:

Copy CodeThe code is as follows:
/data/shell/hello.sh

Method Three: Use bash or sh directly to execute the Bash shell script:

Copy CodeThe code is as follows:
Cd/data/shell

Bash hello.sh

Or

Copy CodeThe code is as follows:
Cd/data/shell

SH hello.sh

Note that if you do this in method three, you do not have to set the execution permissions of the shell beforehand, or even write the first line in the shell file (specify the bash path). Because method three is performed by passing hello.sh as a parameter to the SH (bash) command. This is not hello.sh to execute itself, but is called by others to execute, so do not execute permissions. Then you don't have to specify the bash path nature or understanding Ah, hehe ...

Method Four: Execute the Bash shell script in the current shell environment:

Copy CodeThe code is as follows:
Cd/data/shell

. hello.sh

Or

Copy CodeThe code is as follows:
Cd/data/shell

SOURCE hello.sh

The first three ways to execute a shell script are to open a child shell environment in the current shell (called the parent Shell), which is executed in this child shell environment. When the shell script finishes executing, the child shell environment closes and then goes back to the parent shell. The method four is executed in the current shell.

4 ways to execute shell scripts in Linux summary