CHAPTER
2-1
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
2

Using the Command-Line Interface

This c ha pter d escri bes th e IO S comm an d-l ine int erfa ce ( CLI ) th at you c a n u se to con figure your
switches. It contains these sections:
•IOS Comma nd Modes, pa ge 2-1
•Getting Help, page 2-3
•Abbreviating Com mands, pag e 2-5
•Using no an d default Forms of Comma nds, pag e 2-5
•Understa ndin g C LI M ess ages, page 2-5
•Using Com mand Histo ry, page 2-6
•Using Editing Features, page 2-7
•Searching and Filtering Output of show and more Commands, page 2-10
•Accessi ng the CLI, page 2-10

IOS Command Modes

The Cisco IOS user interface is div ided into many different modes. The commands available to you
depend on whic h mode you are cur re ntly i n. En ter a quest ion ma rk (?) a t the system prompt to obtai n a
list of commands available for each command mode.
When you st art a sessi o n on the swi tch, y ou b egin i n us er mode , o ften cal le d user EXE C m ode . On ly a
limited subset of the commands are av ailable in user EXEC mode. For example, most of the user EXEC
comm ands ar e one-ti me co mmand s, suc h as show commands, which show the current configuration
status, and clear commands, which clear counters or interfaces. The user EXEC commands are not saved
when the switch reboots.
To have access to all commands, you must enter privileged EXEC mode. Normally, you must enter a
password to ent er p rivileged EXE C m od e. Fr om t his m ode , yo u c an en ter any privileged E XEC
comm and or en ter glob al configur ation mo de.
Using the c onfigurati on m odes ( glob al, i nte rface , and l ine ), y ou can ma ke cha ng es t o the ru nning
configuration. If you save the configuration, these commands are stored and used when the switch
reboot s. To acce ss the various c onfigurati on modes, you must sta rt at glo bal c onfigura tion mo de . Fro m
global configurati on mode, y ou can enter interface configurat ion mode an d line co nfiguration mo de.