Extra Unix Shell Material: Glossary

Key Points

Manual Pages
  • man command displays the manual page for a given command.

  • [OPTION]... means the given command can be followed by one or more optional flags.

  • Flags specified after ellipsis are still optional but must come after all other flags.

  • While inside the manual page,use / followed by your pattern to do interactive searching.

Working Remotely
  • SSH is a secure alternative to username/password authorization

  • SSH keys are generated in public/private pairs. Your public key can be shared with others. The private keys stays on your machine only.

  • The ‘ssh’ and ‘scp’ utilities are secure alternatives to logging into, and copying files to/from remote machine

Permissions
  • Correct permissions are critical for the security of a system.

  • File permissions describe who and what can read, write, modify, and access a file.

  • Use ls -l to view the permissions for a specific file.

  • Use chmod to change permissions on a file or directory.

Directory structure
  • FIXME

Job control
  • When we talk of ‘job control’, we really mean ‘process control’

  • A running process can be stopped, paused, and/or made to run in the background

  • A process can be started so as to immediately run in the background

  • Paused or backgrounded processes can be brought back into the foreground

  • Process information can be inspected with ps

Aliases and bash customization
  • Aliases are used to create shortcuts or abbreviations

  • The .bashrc and .bash_profile files allow us to customize our bash environment.

  • The PS1 system variable can be changed to customize your bash prompt.

Shell Variables
  • Shell variables are by default treated as strings

  • The PATH variable defines the shell’s search path

  • Variables are assigned using “=” and recalled using the variable’s name prefixed by “$

The Unix Shell
AWK

Glossary

remote login
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remote login server
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SSH daemon
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secure shell
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SSH key
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SSH protocol
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command
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user name
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user ID
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user group
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user group name
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user group ID
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access control lists
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search path
FIXME