Bash
- Getting started with Bash
- Awesome Book
- Awesome Community
- Awesome Course
- Awesome Tutorial
- Awesome YouTube
- Aliasing
- Arrays
- Associative arrays
- Avoiding date using printf
- Bash Arithmetic
- Bash history substitutions
- Bash on Windows 10
- Bash Parameter Expansion
- Brace Expansion
- Case statement
- CGI Scripts
- Chain of commands and operations
- Change shell
- Color script output (cross-platform)
- Conditional Expressions
- Control Structures
- co-processes
- Copying (cp)
- Creating directories
- Customizing PS1
- Cut Command
- Debugging
- Decoding URL
- Design Patterns
- File execution sequence
- File Transfer using scp
- Find
- Functions
- getopts : smart positional-parameter parsing
- global and local variables
- Grep
- Handling the system prompt
- Here documents and here strings
- Internal variables
- $!
- $#
- $$
- $*
- $?
- $@
- $_
- $1 $2 $3 etc...
- $BASH_ENV
- $BASH_VERSINFO
- $BASH_VERSION
- $BASHPID
- $EDITOR
- $FUNCNAME
- $GROUPS
- $HISTSIZE
- $HOME
- $HOSTNAME
- $HOSTTYPE
- $IFS
- $LINENO
- $MACHTYPE
- $OLDPWD
- $OSTYPE
- $PATH
- $PPID
- $PWD
- $RANDOM
- $SECONDS
- $SHELLOPTS
- $SHLVL
- $UID
- Bash internal variables at a glance
- Job Control
- Jobs and Processes
- Jobs at specific times
- Keyboard shortcuts
- Listing Files
- Managing PATH environment variable
- Math
- Namespace
- Navigating directories
- Networking With Bash
- Parallel
- Pattern matching and regular expressions
- Pipelines
- Pitfalls
- Process substitution
- Programmable completion
- Quoting
- Read a file (data stream, variable) line-by-line (and/or field-by-field)?
- Redirection
- Scoping
- Script shebang
- Scripting with Parameters
- Select keyword
- Sleep utility
- Sourcing
- Splitting Files
- strace
- The cut command
- true, false and : commands
- Type of Shells
- Typing variables
- Using "trap" to react to signals and system events
- Using cat
- Using sort
- When to use eval
- Word splitting
Bash Internal variables $OLDPWD
Example
OLDPWD (OLDPrintWorkingDirectory) contains directory before the last cd command:
~> $ cd directory
directory> $ echo $OLDPWD
/home/user
