Editing Solaris 10 Associate (section)

== Search Files & Directories ==

=== Searching for contents in files ===

Search contents of files for string patterns with <code>grep</code>, <code>egrep</code>, <code>fgrep</code> commands

==== grep command ====

* <code>grep</code> command searches contents one or more file names for a specific character pattern
* grep means globally search for a regular expression & print all lines containing regular expression
* grep does not change file contents
* Syntax: <code>grep options pattern filename</code>

From grep man page:
<pre>
DESCRIPTION
The grep utility searches  text  files  for  a  pattern  and
prints  all lines that contain that pattern.  It uses a com-
pact non-deterministic algorithm.

Be careful using the characters $, *, [, ^, |, (, ),  and  \
in  the pattern_list because they are also meaningful to the
shell. It is safest to enclose the  entire  pattern_list  in
single quotes  '... '.

If no files are specified, grep assumes standard input. Nor-
mally,  each  line  found  is copied to standard output. The
file name is printed before each line found if there is more
than one input file.

OPTIONS
     The following options are supported for  both  /usr/bin/grep
     and /usr/xpg4/bin/grep:

     -b    Precede each line by the block number on which it  was
           found. This can be useful in locating block numbers by
           context (first block is 0).

     -c    Print only a count of the lines that contain the  pat-
           tern.

     -h    Prevents the name of the file containing the  matching
           line  from  being  appended  to  that line.  Used when
           searching multiple files.

     -i    Ignore upper/lower case distinction  during  comparis-
           ons.

     -l    Print only the names of  files  with  matching  lines,
           separated  by NEWLINE characters.  Does not repeat the
           names of files when the pattern  is  found  more  than
           once.

     -n    Precede each line by  its  line  number  in  the  file
           (first line is 1).

     -s    Suppress error messages about nonexistent  or  unread-
           able files.

     -v    Print all lines except those that contain the pattern.

     -w    Search for the expression as a word as  if  surrounded
           by \< and \>.
</pre>

<table style="text-align: left; width: 50%;" align="center" border="1"
 cellpadding="0" cellspacing="0">
    <tr>
      <td></td>
      <td>Definition</td>
    </tr>
    <tr>
      <td>-i</td>
      <td>ignore case sensitivies</td>
    </tr>
    <tr>
      <td>-l</td>
      <td>print only the names of files with matching lines, does
not repeat the names of files when pattern is found &gt;1</td>
    </tr>
    <tr>
      <td>-n</td>
      <td>precedes each line by its line number in the file</td>
    </tr>
    <tr>
      <td>-v</td>
      <td>prints all lines except those that contain the pattern</td>
    </tr>
    <tr>
      <td>-c</td>
      <td>prints only a count of lines that contain the pattern</td>
    </tr>
    <tr>
      <td>-w</td>
      <td>search for the expression as a word as if surrounded by
\&lt; and \&gt;, ignoring matches that are substrings of larger
words</td>
    </tr>
</table>

<insert examples using grep>

===== Regular expression metacharacters =====

<table style="text-align: center; width: 50%;" align="center" border="1"
 cellpadding="0" cellspacing="0">
    <tr>
      <td>Metacharacter</td>
      <td>Purpose</td>
      <td>Example</td>
      <td>Result</td>
    </tr>
    <tr>
      <td>^</td>
      <td>begining of line anchor</td>
      <td>'^pattern'</td>
      <td>matches all lines beginning with pattern</td>
    </tr>
    <tr>
      <td>$</td>
      <td>end of line anchor</td>
      <td>'pattern$'</td>
      <td>matches all lines ending with pattern</td>
    </tr>
    <tr>
      <td>.</td>
      <td>matches one character</td>
      <td>'p.....n'</td>
      <td>matches lines containing a "p", followed by five
characters, and followed by an "n"</td>
    </tr>
<tr>
      <td>*</td>
      <td>matches the preceding item zero or more times</td>
      <td>'[a-z]*'</td>
      <td>matches lowercase alphabet characters only</td>
</tr>
<tr>
      <td>[ ]</td>
      <td>matches one character in a pattern</td>
      <td>'[Pp]attern'</td>
      <td>matches lines containing Pattern or pattern</td>
</tr>
<tr>
      <td>[^]</td>
      <td>matches one character not in the pattern</td>
      <td>'[^a-m]attern'</td>
      <td>matches lines that do not contain a-m and followed by attern</td>
</tr>
</table>

<insert examples regular expression metacharacters>

==== egrep command ====

<code>egrep</code> command searches the contents of one or more files for a pattern using extended regular expression metacharacters (regular expression characters plus more)

Syntax:

<code>egrep options pattern filename</code>

<table style="text-align: center; width: 50%;" align="center" border="1"
 cellpadding="0" cellspacing="0">
    <tr>
      <td>Metacharacter</td>
      <td>Purpose</td>
      <td>Example</td>
      <td>Result</td>
    </tr>
    <tr>
      <td>+</td>
      <td>matches one or more of the preceding characters</td>
      <td>'[a-z]+ark'</td>
      <td>matches one or more lowercase letters followed by ark</td>
    </tr>
    <tr>
      <td>x|y</td>
      <td>matches either x or y</td>
      <td>'boat|airplane'</td>
      <td>matches for either expresssion</td>
    </tr>
    <tr>
      <td>(|)</td>
      <td>group characters</td>
      <td>'(1|2)+'<br>'gam(es|ing)+'</td>
      <td>matches for one or more occurrences (1 or 2, games or gaming)</td>
    </tr>
</table>

===== examples using egrep =====

<insert examples>

search for all lines containing one or more lowercase alphabets followed by the pattern 'body' one or more times, perform the command:

<code>$ egrep '[a-z]+body' /etc/passwd</code>

to search for lines containing the pattern Network Admin or uucp Admin, perform the command:

<code>$ egrep '(Network|uucp) Admin' /etc/passwd</code>

==== fgrep command ====

use fgrep command to search a file for a literal string or group of characters

fgrep commands reads all characters as text (no metacharacters)

syntax:

<code>fgrep options string filename</code>

===== examples using fgrep =====

search for all lines in the file containing an * character, use the command:

<code>$ fgrep '*' /etc/system</code>

search for a string adm in all files in the current directory with the names ending with .sh string, use the command:

<code>$ fgrep adm *.sh</code>

=== searching for files and directories ===


==== find command ====

use <code>find</code> command to locate files or directories in the directory hierarchy

<code>find</code> command recursively descends the directory tree in the path name list, looking for files that match search criteria

as <code>find</code> command matches files matching search criteria the absolute path for each file is displayed on screen

syntax:

<code>find pathname expression action</code>

<code>find</code> command arguments:
* pathname = absolute or relative path where the search originates
* expression = search criteria specified by one or more options. specifying multiple options causes the find command to use the boolean operator <code>and</code>, so all listed expressions must be verified as true
* action = action required after the files have been located. the default print action is to print all path names matching the criteria to the screen

===== find expressions =====

some expressions for <code>find</code> command

<table style="text-align: left; width: 50%;" border="1"
 cellpadding="0" cellspacing="0">
    <tr>
      <td>expression</td>
      <td>definition</td>
    </tr>
    <tr>
      <td>-name filename</td>
      <td>finds files matching the specified filename, metacharacters are acceptable if placed inside quote marks " " or ' '</td>
    </tr>
    <tr>
      <td>-inum [integer]</td>
      <td>finds files by inode #</td>
    </tr>
    <tr>
      <td>-size [+|-]n</td>
      <td>finds files that are > +n or < -n or = n. n is 512-byte blocks</td>
    </tr>
    <tr>
      <td>-atime [+|-]n</td>
      <td>finds files that have been accessed > +n or < -n or = n. n is days</td>
    </tr>
<tr>
      <td>-mtime [+|-]n</td>
      <td>find files that have been modified > +n or < -n or = n. n is days</td>
    </tr>
<tr>
      <td>-user userID</td>
      <td>finds all files that are owned by the userID</td>
    </tr>
<tr>
      <td>-type</td>
      <td>finds a file type, for example f = file and d = directory</td>
    </tr>
<tr>
      <td>-perm</td>
      <td>finds files that have certain access permission bits</td>
    </tr>
</table>

===== find actions =====

<table style="text-align: left; width: 50%;" border="1"
 cellpadding="0" cellspacing="0">
    <tr>
      <td>action</td>
      <td>definition</td>
    </tr>
    <tr>
      <td>-exec command {}  \;</td>
      <td>runs the specified command on each file located. a set of braces { } delimits where the file name is passed to the command from the preceding expressions. a space, backslash, and semicolon (\;) delimits the end of the command. There must be a space before the backslash (\)</td>
    </tr>
<tr>
      <td>-ok command {} \;</td>
      <td>requires confirmation before find command applies the command to each file located. this is the interactive form of the -exec command</td>
    </tr>
<tr>
      <td>-print</td>
      <td>instructs the find command to print the current path name to terminal session. this is the default</td>
    </tr>
<tr>
      <td>-ls</td>
      <td>displays the current path name and associated statistics, such as the inode number, the size in kilobytes, protection mode, the number of hard links, and the user</td>
    </tr>
</table>

===== find examples =====

<insert examples>

search home directory looking for files or directories called deleteme and asking before deleting any matches perform this command:

<code>$ find ~ -name deleteme -ok rm {} \;</code>

to look for all files that have not been modified in the last two days starting in current directory perform this command:

<code>$ find . -mtime +2</code>

remove files without confirmation that have been modified greater than 30 days in current working directory

<code>find . -mtime +30 -exec rm -f {} \;</code>

to find files larger than 10 blocks (512-byte blocks X 10 = 5,120 bytes) starting in your home directory perform this command:

<code>$ find ~ -size +10</code>