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What do braces do in Bash?
Bash brace expansion is used to generate stings at the command line or in a shell script. The syntax for brace expansion consists of either a sequence specification or a comma separated list of items inside curly braces “{}”. A sequence consists of a starting and ending item separated by two periods “..”.
What do parentheses do in Linux?
Parentheses denote a subshell in bash. To quote the man bash page: (list) list is executed in a subshell environment (see COMMAND EXECUTION ENVIRONMENT below). Variable assignments and builtin commands that affect the shell’s environment do not remain in effect after the command completes.
When to use braces, brackets, and parentheses?
Braces are used to group the statements in an if statement, a loop, or other control structures. Brackets (“square brackets”) Brackets are used to index into an array .
What is the difference between parentheses and curly braces in GNU?
Well, GNU Make interpreted $ (smile:) as a variable reference to a variable called smile: and not smile! You can verify that by defining a variable called smile: using this trickery (you have to do that to make a variable called smile: because if you try smile: := foo GNU Make will think you are making a rule to make a file called smile !)
Can a parenthesis be used without a parentheses?
You can refer to the first of the two parentheses as simply a parenthesis, but you can’t have one without the other. One bracket is grammatically incorrect until its second reflected pair is placed.
What’s the difference between braces and brackets in shell scripting?
Doing something like STR2=”$STR2World” won’t work, so you use braces, ie: STR2=”$ {STR}World”. As for brackets, they are used, similar to the backtick, `, which expands the text between them as the text output from a command. What if you wanted to store the current time as a string? Now STR2 stores the string “Thu May 7 09:32:06 PDT 2015”.