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Multiple-line comment for shell scripts

How to comment a block of text without inserting the ‘#’ character to all lines?
We just use a ‘<<COMMENT_STRING’ (COMMENT_STRING can be obviously whatever we want) before the line of text we want to comment out and ‘COMMENT_STRING’ after the last line.

An example:

<<HEADER_COMMENT
This is a test comment - lol!
HEADER_COMMENT

[source1,source2]

ps. In source 1 the “:” is placed in front of the “<<COMMENT_STRING”, which is not mentioned in source 2 and from what I tested with bash scripts it seems not necessary.

Useful small things for c-shell

> When using if statement in c-shell you have to be careful with the syntax:

if (condition) then
(commands)
endif

or if you want to add another case then

if (condition) then
(commands)
else
(commands)
endif

Important to remember that after “then” you must continue to a new line.

> “exit” is the one option to work with if statement, since “break” works only with foreach/while

> If you want to assign the output of a command to a variable the \n you have to place this into backticks ` … ` like:
set test = `grep "test text" temp`

While loop in C-shell scripts

When using the while loop in C-shell scripting the usual stucture is:

while (expression)
commands

end

BUT, you need to add an empty line or a comment after end in order for the loop to work!