carsonip/bash.md

## bash.md

      
    Raw
  

              bash.md
            
          
    Argument
echo $1 $2  # argument by position
echo $@  # all arguments
Default
echo ${x:-default value}  # equiv to python: "x or 'default value'"
Substring
echo ${parameter:offset:length}
Don't stop and also save exit status
set -e
EXIT_CODE=0
command || EXIT_CODE=$?
echo $EXIT_CODE