Sh-file - Revision history

Daniel-schurhoff-de23@rwth-aachen.de at 13:53, 3 September 2019

2019-09-03T13:53:40Z

Christian-wassermann-e30b@rwth-aachen.de at 11:21, 16 April 2018

2018-04-16T11:21:03Z

Christian-wassermann-e30b@rwth-aachen.de at 11:30, 10 April 2018

2018-04-10T11:30:21Z

Ds019135 at 10:00, 28 February 2018

2018-02-28T10:00:08Z

Ds019135: Created page with "== General == A shell script or Sh-file is something between a single command and a (not necessarily) small programm. The basic idea is to couple a few shell commands..."

2018-02-27T17:12:37Z

Created page with "== General == A shell script or Sh-file is something between a single command and a (not necessarily) small programm. The basic idea is to couple a few shell commands..."

New page

== General ==

A [[shell]] script or Sh-file is something between a single command and a (not necessarily) small programm. The basic idea is to couple a few [[shell]] commands together in a file for ease of use. So whenever you tell the [[shell]] to execute that file, it will execute all the specified commands in order. Generally there is one command per line.

== Usage ==
$ bash myscript.sh

starts a (new) instance of the bash shell, which runs the commands specified in 'yourfile.sh'.

To create or write a new shell script file, one can utilize e.g. [[vim]] or a different text editor. Generally a script starts with a shebang specifying the type of shell the script expects (bash in this case)
<syntaxhighlight lang="bash">
#!/bin/bash
</syntaxhighlight>

Following that, one continues with [[shell]] commands, one per line. Comment lines start with '#' and are highly recommended for read- and reusability. Furthermore the 'echo' command is useful to display information on what is currently being done or return results. A minimal shell script might look like this

<syntaxhighlight lang="bash">
#!/bin/bash
echo 'The current directory is:'
# pwd prints the current directory
pwd
echo 'and in this directory you can find:'
# ls -l gives a list of everything of files and subdirectories
ls -l
</syntaxhighlight>
which prints the current directory and a list of the contained subdirectories and files.

== Making a file executable ==
To execute the script without specifying the shell first, one has to make the file executable with
$ chmod +x myscript.sh

and now one can execute the file with
$ ./myscript.sh

However, don't forget the shebang, otherwise this might not work.

== References ==
[https://wiki.ubuntuusers.de/Shell/Bash-Skripting-Guide_f%C3%BCr_Anf%C3%A4nger/ Guide to shell scripting]

← Older revision		Revision as of 13:53, 3 September 2019
Line 1:		Line 1:
		+	[[Category:Basics]]
	== General ==		== General ==

@@ Line 1: / Line 1: @@
 == General ==
-A [[shell]] script or Sh-file is something between a single command and a (not necessarily) small programm. The basic idea is to couple a few [[shell]] commands together in a file for ease of use. So whenever you tell the [[shell]] to execute that file, it will execute all the specified commands in order. This makes it very easy to run a couple of commands and gives one the opportunity to simplify frequent tasks easily.
+A [[shell]] script or sh-file is something between a single command and a (not necessarily) small programm. The basic idea is to chain a few [[shell]] commands together in a file for ease of use. So whenever you tell the [[shell]] to execute that file, it will execute all the specified commands in order. This makes it very easy to run a couple of commands and gives one the opportunity to simplify frequent tasks.
@@ Line 7: / Line 7: @@
   $ bash myscript.sh
-starts a (new) instance of the bash shell, which runs the commands specified in 'yourfile.sh'.
+starts a (new) instance of the bash shell, which runs the commands specified in 'myscript.sh'.
 To create or write a new shell script file, one can utilize e.g. [[vim]] or a different text editor. Generally a script starts with a shebang (#!) specifying the type of shell the script expects (bash in this case)
@@ Line 14: / Line 14: @@
 </syntaxhighlight>
-Following that, one continues with [[shell]] commands, one per line. Comment lines start with '#' and are highly recommended for read- and reusability. Furthermore the 'echo' command is useful to display information on what is currently being done or return results. A minimal shell script might look like this
+Following that, one continues with [[shell]] commands, one per line. Comment lines start with '#' and are highly recommended for improving the readability of the code and later support its reusability for other tasks. Furthermore the 'echo' command is useful to display information on what is currently being done or return results. A minimal shell script might look like this
 <syntaxhighlight lang="bash">

@@ Line 2: / Line 2: @@
 A [[shell]] script or sh-file is something between a single command and a (not necessarily) small programm. The basic idea is to chain a few [[shell]] commands together in a file for ease of use. So whenever you tell the [[shell]] to execute that file, it will execute all the specified commands in order. This makes it very easy to run a couple of commands and gives one the opportunity to simplify frequent tasks.
 == Usage ==
   $ bash myscript.sh
-starts a (new) instance of the bash shell, which runs the commands specified in 'myscript.sh'.
+starts a (new) instance of the bash shell, which runs the commands specified in <code>myscript.sh</code>.
-To create or write a new shell script file, one can utilize e.g. [[vim]] or a different text editor. Generally a script starts with a shebang (#!) specifying the type of shell the script expects (bash in this case)
+To create or write a new shell script file, one can utilize e.g. [[vim]] or a different text editor. Generally a script starts with a shebang (<code>#!</code>) specifying the type of shell the script expects (bash in this case)
 <syntaxhighlight lang="bash">
 #!/bin/bash
 </syntaxhighlight>
-Following that, one continues with [[shell]] commands, one per line. Comment lines start with '#' and are highly recommended for improving the readability of the code and later support its reusability for other tasks. Furthermore the 'echo' command is useful to display information on what is currently being done or return results. A minimal shell script might look like this
+Following that, one continues with [[shell]] commands, one per line. Comment lines start with <code>#</code> and are highly recommended for improving the readability of the code and later support its reusability for other tasks. Furthermore the <code>echo</code> command is useful to display information on what is currently being done or return results. A minimal shell script might look like this:
 <syntaxhighlight lang="bash">
@@ Line 27: / Line 26: @@
 ls -l
 </syntaxhighlight>
 == Making a file executable ==
@@ Line 40: / Line 48: @@
 However, don't forget the shebang, otherwise this might not work.
 == References ==
 [https://wiki.ubuntuusers.de/Shell/Bash-Skripting-Guide_f%C3%BCr_Anf%C3%A4nger/ Guide to shell scripting]