1 | Writing System V init scripts for Red Hat Linux |
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2 | =============================================== |
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3 | |
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4 | All System V init scripts are named /etc/rc.d/init.d/<servicename> |
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5 | where <servicename> is the name of the service. There must be no |
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6 | ".init" suffix. |
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7 | |
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8 | This path will very likely be moved to /etc/init.d in the future. |
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9 | Once Red Hat Linux 7.0 is installed, you can access scripts as |
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10 | /etc/init.d/<servicename>, via symlinks. |
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11 | |
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12 | Sample Script |
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13 | ============= |
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14 | |
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15 | #!/bin/bash |
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16 | # |
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17 | # /etc/rc.d/init.d/<servicename> |
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18 | # |
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19 | # <description of the *service*> |
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20 | # <any general comments about this init script> |
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21 | # |
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22 | # <tags -- see below for tag definitions. *Every line* from the top |
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23 | # of the file to the end of the tags section must begin with a # |
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24 | # character. After the tags section, there should be a blank line. |
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25 | # This keeps normal comments in the rest of the file from being |
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26 | # mistaken for tags, should they happen to fit the pattern.> |
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27 | |
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28 | # Source function library. |
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29 | . /etc/rc.d/init.d/functions |
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30 | |
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31 | <define any local shell functions used by the code that follows> |
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32 | |
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33 | start() { |
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34 | echo -n "Starting <servicename>: " |
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35 | <start daemons, perhaps with the daemon function> |
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36 | touch /var/lock/subsys/<servicename> |
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37 | return <return code of starting daemon> |
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38 | } |
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39 | |
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40 | stop() { |
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41 | echo -n "Shutting down <servicename>: " |
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42 | <stop daemons, perhaps with the killproc function> |
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43 | rm -f /var/lock/subsys/<servicename> |
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44 | return <return code of stopping daemon> |
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45 | } |
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46 | |
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47 | case "$1" in |
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48 | start) |
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49 | start |
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50 | ;; |
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51 | stop) |
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52 | stop |
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53 | ;; |
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54 | status) |
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55 | <report the status of the daemons in free-form format, |
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56 | perhaps with the status function> |
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57 | ;; |
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58 | restart) |
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59 | stop |
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60 | start |
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61 | ;; |
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62 | reload) |
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63 | <cause the service configuration to be reread, either with |
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64 | kill -HUP or by restarting the daemons, in a manner similar |
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65 | to restart above> |
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66 | ;; |
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67 | condrestart) |
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68 | <Restarts the servce if it is already running. For example:> |
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69 | [ -f /var/lock/subsys/<service> ] && restart || : |
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70 | probe) |
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71 | <optional. If it exists, then it should determine whether |
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72 | or not the service needs to be restarted or reloaded (or |
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73 | whatever) in order to activate any changes in the configuration |
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74 | scripts. It should print out a list of commands to give to |
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75 | $0; see the description under the probe tag below.> |
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76 | ;; |
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77 | *) |
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78 | echo "Usage: <servicename> {start|stop|status|reload|restart[|probe]" |
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79 | exit 1 |
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80 | ;; |
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81 | esac |
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82 | exit $? |
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83 | |
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84 | Notes: |
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85 | |
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86 | - The restart and reload functions may be (and commonly are) |
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87 | combined into one test, vis: |
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88 | restart|reload) |
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89 | - You are not prohibited from adding other commands; list all commands |
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90 | which you intend to be used interactively to the usage message. |
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91 | - Notice the change in that stop() and start() are now shell functions. |
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92 | This means that restart can be implemented as |
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93 | stop |
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94 | start |
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95 | instead of |
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96 | $0 stop |
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97 | $0 start |
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98 | This saves a few shell invocations. |
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99 | |
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100 | Functions in /etc/rc.d/init.d/functions |
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101 | ======================================= |
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102 | |
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103 | daemon [ --check <name> ] [ --user <username>] |
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104 | [+/-nicelevel] program [arguments] [&] |
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105 | |
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106 | Starts a daemon, if it is not already running. Does |
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107 | other useful things like keeping the daemon from dumping |
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108 | core if it terminates unexpectedly. |
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109 | |
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110 | --check <name>: |
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111 | Check that <name> is running, as opposed to simply the |
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112 | first argument passed to daemon(). |
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113 | --user <username>: |
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114 | Run command as user <username> |
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115 | |
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116 | killproc program [signal] |
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117 | |
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118 | Sends a signal to the program; by default it sends a SIGTERM, |
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119 | and if the process doesn't die, it sends a SIGKILL a few |
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120 | seconds later. |
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121 | |
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122 | It also tries to remove the pidfile, if it finds one. |
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123 | |
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124 | pidofproc program |
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125 | |
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126 | Tries to find the pid of a program; checking likely pidfiles, |
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127 | and using the pidof program. Used mainly from within other |
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128 | functions in this file, but also available to scripts. |
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129 | |
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130 | status program |
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131 | |
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132 | Prints status information. Assumes that the program name is |
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133 | the same as the servicename. |
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134 | |
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135 | |
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136 | Tags |
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137 | ==== |
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138 | |
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139 | # chkconfig: <startlevellist> <startpriority> <endpriority> |
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140 | |
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141 | Required. <startlevellist> is a list of levels in which |
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142 | the service should be started by default. <startpriority> |
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143 | and <endpriority> are priority numbers. For example: |
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144 | # chkconfig: 2345 20 80 |
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145 | Read 'man chkconfig' for more information. |
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146 | |
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147 | Unless there is a VERY GOOD, EXPLICIT reason to the |
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148 | contrary, the <endpriority> should be equal to |
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149 | 100 - <startpriority> |
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150 | |
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151 | # description: <multi-line description of service> |
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152 | |
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153 | Required. Several lines of description, continued with '\' |
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154 | characters. The initial comment and following whitespace |
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155 | on the following lines is ignored. |
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156 | |
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157 | # description[ln]: <multi-line description of service in the language \ |
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158 | # ln, whatever that is> |
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159 | |
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160 | Optional. Should be the description translated into the |
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161 | specified language. |
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162 | |
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163 | # processname: |
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164 | |
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165 | Optional, multiple entries allowed. For each process name |
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166 | started by the script, there should be a processname entry. |
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167 | For example, the samba service starts two daemons: |
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168 | # processname: smdb |
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169 | # processname: nmdb |
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170 | |
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171 | # config: |
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172 | |
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173 | Optional, multiple entries allowed. For each static config |
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174 | file used by the daemon, use a single entry. For example: |
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175 | # config: /etc/httpd/conf/httpd.conf |
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176 | # config: /etc/httpd/conf/srm.conf |
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177 | |
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178 | Optionally, if the server will automatically reload the config |
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179 | file if it is changed, you can append the word "autoreload" to |
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180 | the line: |
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181 | # config: /etc/foobar.conf autoreload |
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182 | |
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183 | # pidfile: |
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184 | |
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185 | Optional, multiple entries allowed. Use just like the config |
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186 | entry, except that it points at pidfiles. It is assumed that |
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187 | the pidfiles are only updated at process creation time, and |
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188 | not later. The first line of this file should be the ASCII |
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189 | representation of the PID; a terminating newline is optional. |
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190 | Any lines other than the first line are not examined. |
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191 | |
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192 | # probe: true |
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193 | |
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194 | Optional, used IN PLACE of processname, config, and pidfile. |
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195 | If it exists, then a proper reload-if-necessary cycle may be |
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196 | acheived by running these commands: |
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197 | |
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198 | command=$(/etc/rc.d/init.d/SCRIPT probe) |
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199 | [ -n "$command" ] && /etc/rc.d/init.d/SCRIPT $command |
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200 | |
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201 | where SCRIPT is the name of the service's sysv init script. |
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202 | |
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203 | Scripts that need to do complex processing could, as an |
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204 | example, return "run /var/tmp/<servicename.probe.$$" |
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205 | and implement a "run" command which would execute the |
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206 | named script and then remove it. |
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207 | |
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208 | Note that the probe command should simply "exit 0" if nothing |
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209 | needs to be done to bring the service into sync with its |
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210 | configuration files. |
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211 | |
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212 | Copyright (c) 2000 Red Hat Software, Inc. |
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