| banner | |
|---|---|
| Operating system | Unix andUnix-like |
| Type | Command |
Thebannerprogram onUnix andUnix-likeoperating systems outputs a largeASCII art version of the text that is supplied to it as itsprogram arguments. One use of the command is to create highly visible separator pages forprint jobs.[1]
Each argument is truncated at 10 characters and printed on a "line" of its own. To print multiple words on a single line, they must therefore be passed as a single argument, which is done from theshell by escaping or quoting the words as appropriate.[1]
A related and more flexible program isFIGlet, which can display text in different fonts and orientations.[2]
The way that the program is implemented internally is antiquated. The character fonts used are hardwired into the program code itself, as statically initialized data structures. Two data structures are used. The first is a data table comprising a sequence of printing instructions that encode the bitmap for each character (in an encoding specific to thebanner program). The second is an index into that table that indicates, for each character code, where the printing instructions for that character begin and end.[3]
Both data structures were hand-written. Spinellis observes that it is "difficult to come up with a more error-prone and unmaintainable data format". He observes a stark contrast between the source code of thebanner program and automatically generated source code for encoding computer fonts into program data (using the 6-by-10 font data in the source code of the mac68k port ofNetBSD for comparison). The automatically generated data are commented, documenting with ASCII art how the bit patterns were derived. The automatically generated data were generated from a bitmap file, itself generated using a bitmap creation/editing program with a graphical user interface. And the automatically generated data are organized in a straightforward and obvious manner — a fixed-length sequence of unencoded bytes for eachglyph.[3]
Spinellis further observes that in modern computer systems it is seldom sensible to embed such data into the program executable image itself, the performance gains of doing so being negligible. Doing so makes it difficult to adapt the program to different locales, or to maintain the program. The more preferred approach in modern systems is to store such data in a separate data file, distinct from the program executable image file, or in aresource fork of the program, that the program reads at run-time.[3]
A partial list of versions:
From the terminal-oriented banner program:
$banner'Hello!'# # #### # ###### # # #### #### # # # # # # ########## ##### # # # # ## # # # # # ## # # # # # # #### # ###### ###### ###### #### ###
One letter from the printer-oriented banner program as usually found inBSD and derivatives:
$banner-w80"a"############################# ################### ######################## ############# ##### ############# #### ## ###### #### ##### ### ##### ### ####### ### #########################################################################################################################################################
Display a continuous clock for approximately 1000 seconds:[a][b]
$repeat1000sh-c'( clear ; date +" %H.%M.%S" | xargs banner ; sleep 1)'# ##### # ##### ####### ######### # # ## # # # ## # # # # # # ## ###### # ##### ###### ####### # # ### # # ### # ## # # ### # # ### # # # ###### ##### ### ##### ####### ### ##### #####
functionrepeat(){for((i=0;i<$1;i++));doeval${*:2}}
or that definition can be avoided by replacing the repeat command with awhile loop, like this:
$i=0;while(($i<1000));dosh-c'( clear ; date +" %H.%M.%S" | xargs banner ; sleep 1 ; ((i=$i+1)))';done
banner withfiglet -f banner| File system | |
|---|---|
| Processes | |
| User environment | |
| Text processing | |
| Shell builtins | |
| Searching | |
| Documentation | |
| Software development | |
| Miscellaneous | |
