1.1-shell characteristics

!! Executes the previous command!cat executes the most recent command that starts with cat

Cat!$ Execute command, above one command last parameter defines alias for parameter alias

Unalias aliases alias alias is valid only in the current environment, the child shell takes effect and needs to be declared Explort.

Permanent entry, Edit home directory. BASHRC

Wildcard characters

* Match any number of characters? Match any single character

echo $HISTSIZE History command saves 1000 variables by default

Each user has a different history. Configuration files in the home directory. Bash_history

Pipe symbol | Command result before pipeline, command processing after handing to pipeline

redirect > Correct overwrite redirect >> correct append redirect (cannot redirect error result)

2> Error Overwrite redirect 2>> error append redirect

< reverse redirect (subsequent results are given to previous processing) For example: Wc-l < 1.txt

CTRL + Z pause process can use jobs to view a paused background process

FG Tuning background suspend process to foreground execution

BG Tuning background suspend process to background execution

1.1-shell characteristics