88 lines
3.0 KiB
HTML
88 lines
3.0 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<html>
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<head>
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<meta name="generator" content="HTML Tidy, see www.w3.org">
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<meta http-equiv="Content-Type" content=
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"text/html; charset=utf-8">
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<title>Putting it all together in a script</title>
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<LINK rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</HEAD>
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<body bgcolor="#FFFFFF">
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<!-- Java sync-link -->
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<SCRIPT LANGUAGE="Javascript" SRC="../rzahg/synch.js" TYPE="text/javascript"></SCRIPT>
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<p></p>
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<h2>Putting it all together in a script</h2>
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<p>
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The following example shows a simple shell script that illustrates the features of the shell interpreter and utilities. The script takes one input parameter that is the name of a directory. The script then copies all of the files with the .java extension from the input directory to the current directory, keeping a count of the files it copied.</p>
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<p><pre>
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1 # Get a list of files
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2 filelist=$(ls ${1}/*.java)
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3 count=0
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4 # Process each file
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5 for file in $filelist ; do
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6 # Strip directory name
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7 target=${file##*/}
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8 # Copy file to current directory
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9 cp $file $target
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10 count=$((count+=1))
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11 # Print message
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12 print Copied $file to $target
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13 done
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14 print Copied $count files
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</pre>
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<p>
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On lines 1, 4, 6 ,8, 11, the # character denotes a comment. Any characters after the # character are not interpreted by qsh.</p>
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<p>
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On line 2, the variable filelist is set to the output from the <a href="ls.htm">ls</a> command. The ${1} expands to the first input parameter and the *.java expands to all of the files with the .java extension.</p>
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<p>
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On line 3, the variable count is set to zero.</p>
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<p>
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On line 5 is a for loop. For each iteration of the loop. the variable file is set to the next element in the variable filelist. Each element is delimited by a field separator. The default field separators are tab, space, and newline. The semicolon character is a command delimiter and allows you to put more than one command on a line.</p>
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<p>
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On line 7, the variable target is set to the file name from the fully-qualified path name. The ${file##*/} parameter expansion removes the largest pattern starting from the left that matches all characters up to the last slash character.</p>
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<p>
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On line 9, the file is copied with the <a href="cp.htm">cp</a> utility from the specified directory to the current working directory.</p>
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<p>
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On line 10, the variable count is incremented by one.</p>
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<p>
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On line 12, a message is printed using the <a href="print.htm">print</a> utility with the files that were copied.</p>
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<p>
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On line 13, the done marks the end of the for loop.</p>
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<p>
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On line 14, a message is printed with the total number of files that were copied.</p>
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<p>
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If the directory /project/src contained two files with the .java extension and the script is called using the command:
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<p><pre>
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javacopy /project/src
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</pre>
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<p>
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then the output from the script is</p>
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<p><pre>
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Copied /project/src/foo.java to foo.java
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Copied /project/src/bar.java to bar.java
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Copied 2 files
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</pre>
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<p></p>
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</body>
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</html>
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