了解管道：PHP -c

Question

I am having trouble understanding this Linux command:
php -r "readfile('https://getcomposer.org/installer');" | php -c php.ini

It appears the first part php -r is piping to php -c . But it appears php.ini is being read .

Where can I find out more about php command options and they mean (-v and -c), and thus find out what the command is doing?

Answer 1

From man php :

OPTIONS --interactive -a Run PHP interactively. This lets you enter snippets of PHP code that directly get executed. When readline sup‐ port is enabled you can edit the lines and also have history support.

  --bindpath address:port|port -b address:port|port Bind Path for external FASTCGI Server mode (CGI only). --no-chdir -C Do not chdir to the script's directory (CGI only). --no-header -q Quiet-mode. Suppress HTTP header output (CGI only). --timing count -T count Measure execution time of script repeated count times (CGI only). --php-ini path|file -c path|file Look for php.ini file in the directory path or use the specified file --no-php-ini -n No php.ini file will be used --define foo[=bar] -d foo[=bar] Define INI entry foo with value bar -e Generate extended information for debugger/profiler --file file -f file Parse and execute file --help -h This help --hide-args -H Hide script name (file) and parameters (args...) from external tools. For example you may want to use this when a php script is started as a daemon and the command line contains sensitive data such as passwords. --info -i PHP information and configuration --syntax-check -l Syntax check only (lint) --modules -m Show compiled in modules --run code -r code Run PHP code without using script tags '<?..?>' --process-begin code -B begin_code Run PHP begin_code before processing input lines --process-code code -R code Run PHP code for every input line --process-file file -F file Parse and execute file for every input line --process-end code -E end_code Run PHP end_code after processing all input lines --syntax-highlight -s Output HTML syntax highlighted source --server addr:port -S addr:port Start built-in web server on the given local address and port --docroot docroot -t docroot Specify the document root to be used by the built-in web server --version -v Version number --strip -w Output source with stripped comments and whitespace --zend-extension file -z file Load Zend extension file args... Arguments passed to script. Use '--' args when first argument starts with '-' or script is read from stdin --rfunction name --rf name Shows information about function name --rclass name --rc name Shows information about class name --rextension name --re name Shows information about extension name --rzendextension name --rz name Shows information about Zend extension name --rextinfo name --ri name Shows configuration for extension name --ini Show configuration file names 

From php.net:

Usage: php [options] [-f] [--] [args...] php [options] -r [--] [args...] php [options] [-B ] -R [-E ] [--] [args...] php [options] [-B ] -F [-E ] [--] [args...] php [options] -- [args...]
php [options] -a [--] [args...] php [options] [-B ] -R [-E ] [--] [args...] php [options] [-B ] -F [-E ] [--] [args...] php [options] -- [args...]
php [options] -a

-a Run interactively -c | Look for php.ini file in this directory -n No php.ini file will be used -d foo[=bar] Define INI entry foo with value 'bar' -e Generate extended information for debugger/profiler -f
Parse and execute . -h This help -i
PHP information -l Syntax check only (lint) -m
Show compiled in modules -r Run PHP without using script tags -B Run PHP before processing input lines -R Run PHP for every input line -F Parse and execute for every input line -E Run PHP after processing all input lines -H Hide any passed arguments from external tools. -S : Run with built-in web server. -t Specify document root for built-in web server. -s
Output HTML syntax highlighted source. -v Version number -w Output source with stripped comments and whitespace. -z Load Zend extension .

args... Arguments passed to script. Use -- args when first argument starts with - or script is read from stdin

--ini Show configuration file names

--rf Show information about function . --rc Show information about class . --re
Show information about extension . --rz Show information about Zend extension . --ri Show configuration for extension .

Edit:

php -r "readfile('https://getcomposer.org/installer');" | php -c php.ini 

This command runs the file https://getcomposer.org/installer using php.ini in the current directory as the config file. The same can be achieved with

php -r "require('https://getcomposer.org/installer');" -c php.ini

Answer 2

Running php with the -c option simply tells it where to find its configuration file. The -r option tells it to run the code provided.

What your command is doing is fetching some remote PHP code and then piping it to another PHP process to be executed.

Unless you happen to have a special configuration requirement (and have a php.ini file in the current directory) the -c option isn't needed.

I don't recommend doing this, by the way. It's an unnecessary risk to run unknown code on your machine, even it it appears to be coming from a known source.