4 ways to execute shell script commands in Linux

There are several ways to bash a shell script, and now make a summary. Suppose we write a good shell script with the file name hello.sh, the file location in the/data/shell directory and have 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 the Code code 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 could not 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 $PASH command is available to view the contents of the path. Now the/data/shell is not in the environment variable pash, so you must add./To execute.

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

Copy the Code code as follows:
/data/shell/hello.sh

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

Copy the Code code as follows:

Cd/data/shell

Bash hello.sh

Or

Copy the Code code 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 the Code code as follows:
Cd/data/shell

. hello.sh

Or

Copy the Code code 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 script commands in Linux