Section 12.4. CLI Environment -- 追寻梦想＞编程乐园＞PHP 编程

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12.4. CLI Environment

PEAR lets you include command-line scripts in a package. However, when doing so, you will quickly run into configuration problems like, "Which include_path should I use here" or "What is the full path of the PHP executable that should be used?" This information may be specified by users in a set of environment variables, as shown in Table 12.1.

Table 12.1. PEAR Installer Environment Variables
Environment Variable	Corresponding Configuration Parameter
`PHP_PEAR_SYSCONF_DIR`	`none`
`PHP_PEAR_MASTER_SERVER`	`master_server`
`PHP_PEAR_HTTP_PROXY`	`http_proxy`
`PHP_PEAR_INSTALL_DIR`	`php_dir`
`PHP_PEAR_EXTENSION_DIR`	`ext_dir`
`PHP_PEAR_DOC_DIR`	`doc_dir`
`PHP_PEAR_BIN_DIR`	`bin_dir`
`PHP_PEAR_DATA_DIR`	`data_dir`
`PHP_PEAR_TEST_DIR`	`test_dir`
`PHP_PEAR_CACHE_DIR`	`cache_dir`
`PHP_PEAR_PHP_BIN`	`php_bin`
`PHP_PEAR_VERBOSE`	`verbose`
`PHP_PEAR_PREFERRED_STATE`	`preferred_state`
`PHP_PEAR_UMASK`	`umask`
`PHP_PEAR_CACHE_TTL`	`cache_ttl`
`PHP_PEAR_SIG_TYPE`	`sig_type`
`PHP_PEAR_SIG_BIN`	`sig_bin`
`PHP_PEAR_SIG_KEYDIR`	`sig_keydir`

If any of this information is needed during bootstrapping of a PHP script, these environment variables should be used. The PEAR installer uses these environment variables when it sets up default values for its configuration parameters.

Here is an example of a UNIX command-line scripts, using the PHP_PEAR_PHP_BIN environment variable to find the right PHP binary:

#!/bin/sh
export PHP_PEAR_PHP_BIN=${PHP_PEAR_PHP_BIN:-php}
exec $PHP_PEAR_PHP_BIN d output_buffering=1 $0 $@
<?php
ob_end_clean();
print "PHP " . phpversion() . " on " . php_uname() . "\n";

PHP embedded in UNIX shell script. What happens here is that the PHP_PEAR_PHP_BIN is set to either its current existing value or to php if it is not set. Then, the shell script exec's (replaces itself with) PHP with a parameter that enables output buffering, followed by the name of the script and all the command-line parameters. When PHP starts executing the file, it would normally just display the second and third line with shell script code, but because it is running with output buffering enabled, these lines are just buffered. In the PHP block, ob_end_clean() ends output buffering and discards the output so far, so PHP never displays the shell code:
```
@echo off

if "%OS"=="Windows_NT" @setlocal
if "%PHP_PEAR_PHP_BIN%"=="" goto useDefault
goto run
:useDefault
set PHP_PEAR_PHP_BIN=php.exe
:run
%PHP_PEAR_PHP_BIN% -d output_buffering=1 %~dp0 %1 %2 %3 %4 %5 %6 %7 
%8 %9
<?php
ob_end_clean();
print "PHP " . phpversion() . " on " . php_uname() . "\n";
```
PHP embedded in a Windows .bat file. The basic approach here is the same as in the UNIX shell example. The PHP_PEAR_PHP_BIN environment variable is used to getting the right PHP executable, defaulting to just php.exe. (One limitation to note for .bat scripts is that you cannot pass more than nine parameters.)

12.4. CLI Environment

Table 12.1. PEAR Installer Environment Variables