Enable shell

Enable shell linux 

router(config)#shell processing full

show shell environment

router#sh shell environment
# Environment Variables:
# User Environment Variables:
?=1
# Global Environment Variables:
# Builtin Environment Variables:
PATH=CLI%Userfunctions%Builtins%SYSTEM
# Environment Functions:

# User Environment Functions:

# Global Environment Functions:

# Builtin Environment Functions:

Function namespace: DEFAULT
((              evaluate a numeric test expression


Function namespace: DEFAULT
[[              evaluate a logical test expression


Function namespace: DEFAULT
cat             output data from a pipe or file to the terminal


Function namespace: DEFAULT
cut             edit piped output


Function namespace: DEFAULT
echo            echo arguments to the terminal


Function namespace: DEFAULT
false           return false in while or if expressions, and set the result


Function namespace: DEFAULT
fetch           return values from the configuration database


Function namespace: DEFAULT
grep            search for regular expressions in piped output or files


Function namespace: DEFAULT
head            print the first lines in the input


Function namespace: DEFAULT
interface       print interfaces that match the argument


Function namespace: DEFAULT
let             evaluate a numeric expression, and set the result


Function namespace: DEFAULT
man             print information for builtins


Function namespace: DEFAULT
more            page piped output to the terminal


Function namespace: DEFAULT
nl              number the lines in the input


Function namespace: DEFAULT
null            ignore the input


Function namespace: DEFAULT
printf          output formatted data to the terminal


Function namespace: DEFAULT
read            read input into variables


Function namespace: DEFAULT
set_oper        set operational values


Function namespace: DEFAULT
sleep           pause execution of the terminal


Function namespace: DEFAULT
sort            sort the input


Function namespace: DEFAULT
tail            print the tail of the input


Function namespace: DEFAULT
true            return true in while or if expressions, and set the result


Function namespace: DEFAULT
uname           print system information


Function namespace: DEFAULT
wc              count lines, words, and chars

Example

router#sh int desc | grep up
Et0/0                          up             up
Et0/1                          up             up
Lo0                            up             up
NV0                            up             up
Tu0                            up             up

router#sh int desc | grep up | wc -l
4