| Unix terminology. A shell script is an executable file containing a sequence of commands that are run, one-by-one, by a shell.
The first line of a shell script tells the OS what shell should be used to execute it.& FEx, #!/bin/tcsh means that the tcsh shell should be used to run the contents of the script.
Analogous to a batch file.
#!/bin/sh
echo Hello, world!
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