Linux in a Nutshell, Fifth Edition

getopts | 667

Bash and Korn

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before retesting cond. Any one of the expressions may be omitted; a

missing cond is treated as being true.

Examples

Search for a phrase in each odd chapter:

for ((x=1; x <= 20; x += 2))

do

grep $1 chap$x

done

function

function name { commands; }

function name ( ) { commands; }

Define name as a shell function. See the description of semantic

issues in the earlier section “Functions.” The first form is for the

Korn shell, although it may also be used with Bash. The second

form is specific to Bash. Bash does not give different semantics to

functions declared differently; all Bash functions behave the same

way.

Example

Define a function to count files:

$ function fcount {

> ls | wc -l

> }

functions

functions

Korn shell alias for typeset -f. (Note the “s” in the name; function

is a Korn shell keyword.) See typeset later in this listing.

getconf

getconf [name [path]]

ksh93 only. Retrieve the values for parameters that can vary across

systems. name is the parameter to retrieve; path is a filename to test

for parameters that can vary on different filesystem types.

The parameters are defined by the POSIX 1003.1 standard. See the

entry for getconf in Chapter 3.

Example

Print the maximum value that can be held in a C int:

$ getconf INT_MAX

2147483647

getopts

getopts [-a name] string name