This Bash shell scripting guide is not a detailed study but a quick reference to the BASH syntax. So lets begin...Common environment variablesPATH - Sets the search path for any executable command. Similar to the PATH variable in MSDOS.HOME - Home directory of the user.MAIL - Contains the path to the location where mail addressed to the user is stored. IFS - Contains a string of characters which are used as word seperators in the command line. The string normally consists of the space, tab and the newline characters. To see them you will have to do an octal dump as follows:$ echo $IFS | od -b...