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→Part 3: Manage & Manipulate Text File Content
# Refer to the following table of '''Text File Management Commands:'''<br><br><table cellpadding="5"><tr><th style="border-bottom: 1px solid black;" width="20%">Linux Command</th><th style="border-bottom: 1px solid black;">Purpose</th></tr><tr><td style="font-family:courier">'''touch'''</td><td>Create empty file(s) / Updates Existing File's Date/Time Stamp</td></tr><tr><td style="font-family:courier">'''cat'''</td><td>Display text file's contents without editing (small files)</td></tr><tr><td style="font-family:courier">'''more , less'''</td><td>Display / Navigate within large text files without editing</td></tr><tr><td style="font-family:courier">'''cp'''</td><td>Copy text file(s)</td></tr><tr><td style="font-family:courier">'''mv'''</td><td>Move / Rename text files</td></tr><tr><td style="font-family:courier">'''rm'''</td><td>Remove text file(s)</td></tr><tr valign="top"><td style="font-family:courier">'''sort'''</td><td>Sorts (rearranges) order of file contents when displayed. Content is sorted alphabetically by default. The '''-n'''''Italic text'' option sorts numerically, '''-r''' performs a reverse sort</td></tr><tr valign="top"><td style="font-family:courier">'''head''' , '''tail'''</td><td>Displays the first / last 10 lines of a text file by default. An option using a value will display the number of lines (e.g. <span style="font-family:courier">head -5 filename</span> will display first 5 lines, <span style="font-family:courier">tail -5 filename</span> will display last 5 lines).</td></tr><tr valign="top"><td style="font-family:courier">'''grep'''</td><td>Displays file contents that match a pattern</td></tr><tr valign="top"><td style="font-family:courier">'''uniq'''</td><td>Displays identical consecutive lines only once</td></tr><tr valign="top"><td style="font-family:courier">'''diff''' file1 file2</td><td>Displays differences between 2 files</td></tr><tr><td style="font-family:courier">'''file'''</td><td>Gives info about the contents of the file (e.g. file with no extention)</td></tr><tr><td style="font-family:courier">'''find'''</td><td>To find files matching specified characteristics: <!-- <table><tr><td width="30%">'''<span style="font-family:courier">find . -name "file*"</span>'''</td><td>List pathname of any filenames beginning with "file",<br>from the current directory and any subdirectories</td></tr><tr valign="top"><td>'''<span style="font-family:courier">find . -size +50k</span>'''</td><td>List pathname of any files larger than 50 kb, from the current directory and any subdirectories</td></tr><tr valign="top"><td>'''<span style="font-family:courier">find . -mmin -5</span>''' </td><td>List files modified less than 5 minutes ago</td></tr><tr> valign="top"><td>'''<span style="font-family:courier">find -P .</span>'''</td><td>Lists file pathnames in the current directory</td></tr></table> --> </td></tr></table><br>
# Issue the following Linux command to create three <u>empty</u> text files in your current directory:<br><span style="color:blue;font-weight:bold;font-family:courier;">touch a.txt b.txt c.txt</span><br><br>
# Issue the following Linux command: <span style="color:blue;font-weight:bold;font-family:courier;">ls -l a.txt b.txt c.txt</span><br><br>Check the size in the detailed listing to confirm that these newly-created files are empty.<br><br>[[Image:vi-screen-40.png|right|300px|thumb|Nano text editor containing numbers '''1 to 40'''<br>on separate lines.]]
# Use the '''nano''' text editor to edit the empty file called '''a.txt'''. <br><br>Type the number "'''1'''" and press '''ENTER'''. On the second line, type the number "'''2'''" and press '''ENTER'''.<br>Continue entering increasing number values until you reach the number '''40''' on line 40<br>(refer to the diagram on the right).<br><br>
# '''Save''' and '''exit''' your editing session.<br><br>