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Syntax of a Shell Command
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Linux IS Case Sensitive
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In Linux, commands, options, folder, filenames… are Case Sensitive. |
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# Lists what is in the current location. [<username>@<hostname> ~]$ ls Desktop Documents Downloads # Throws an error. [<username>@<hostname> ~]$ LS -bash: LS: command not found Filename ≠ FiLeNaMe ≠ FILENAME |
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| Note |
Remember: |
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Getting Help: man
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Linux has a number of ways to find help on commands. The first is man - “manual”. |
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[<username>@<hostname> ~]$ man ls
LS(1) User Commands LS(1)
NAME
ls - list directory contents
SYNOPSIS
ls [OPTION]... [FILE]...
DESCRIPTION
List information about the FILEs (the current directory by default). Sort entries alpha‐
betically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all
do not ignore entries starting with .
-A, --almost-all
do not list implied . and ..
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Manual page ls(1) line 1 (press h for help or q to quit) |
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Getting Help: <command --help>
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The next method is to use a command's |
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[<username>@<hostname> ~]$ ls --help
Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all do not ignore entries starting with .
-A, --almost-all do not list implied . and ..
--author with -l, print the author of each file
-b, --escape print C-style escapes for nongraphic characters
--block-size=SIZE with -l, scale sizes by SIZE when printing them;
e.g., '--block-size=M'; see SIZE format below
-B, --ignore-backups do not list implied entries ending with ~
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Getting Help: Options
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Typically, options can have a:
Short options can be grouped:
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Single vs Multiple Lines
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If you have a long command, which is difficult to read over a single line, you can split it up across multiple lines. To split, at the end of the line where you want to split type You can continue to split across multiple lines. Once you’re ready to execute, simply press |
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[<username>@<hostname> ~]$ ls -al ~
[<username>@<hostname> ~]$ ls \
> -al \
> ~ |
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Exercises
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Questions:
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Answers(1)
1: Is there a difference between running ls versus ls -al?
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