1. CSCI 330 - The UNIX System Shell History and Directory Stacks
NIU - Department of Computer Science

2. The C Shell
Shell History
shell keeps a record of previously entered commands so that they can later be:
Re-executed
Edited
Commands are saved
Per session
Per user
CSCI The UNIX System
Copyright Department of Computer Science, Northern Illinois University, 2005

3. The C Shell
Shell History
Each previously run command gets a sequential event number
To view the history buffer:
Syntax: history [-c] [count]
If no options are supplied, list all
Useful options:
-c clear history
CSCI The UNIX System
Copyright Department of Computer Science, Northern Illinois University, 2005

4. Shell History You can re-execute history events: By the event number
The C Shell
Shell History
You can re-execute history events:
By the event number
% !5
By the number relative to current event
% !-3
By the text it contains
% !ls
CSCI The UNIX System
Copyright Department of Computer Science, Northern Illinois University, 2005

5. The C Shell
Directory Stacks
To keep track of multiple directories using stack structure
To maintain a directory stack, we use the following three commands:
pushd
popd
dirs
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6. PUSHD pushd (with no argument) to travel between two top stack entries
The C Shell
PUSHD
pushd (with no argument)
to travel between two top stack entries
pushd directory
to push directory on top of stack
pushd +n
to rotate nth entry to the top of stack
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7. POPD AND DIRS popd (with no argument)
The C Shell
POPD AND DIRS
popd (with no argument)
to remove the top directory and changes to the next stack entry
popd +n
to remove the nth directory from stack
dirs:
to display all directory entries.
The top entry is listed at the leftmost position
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