A script is a (bash) program. It consists of grouping a command set in a file and giving the rights in execution of this file.
The first line of the script is a particular line, indicating to the operating system that it is the interpreter to use.
In this case, the line starts by
#! followed by the path to the shell.1
In bash, any line starting with a
# is not interpreted beyond that
# indicates the start of a comment.
A command line in bash ends either by a carriage return (
\n), either by a semi-colon (
If a command must continue to the next line, the continuation character
\ must be used.
#!/bin/bash echo Hello # a comment ls echo a; echo b echo hello\ world
cat > script1 << END #!/bin/bash echo Hello END chmod +x script1 ./script1
this can be obtained via the