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Using the find and grep commands

I put together a list of some of the basic find and grep commands that I use often. The find command recursively searches a directory tree for the files that match the given options.

To find a file in any directory, starting in your current directory
$ find . -name filename

If you do not know the complete filename,use the wildcard * at the start and end of the filename.
$ find . -name *partialfilename* -print

Find only files (not directories) from your current directory. For example,
$ find . -type -f -print
And to find only directory files,type
$ find . -type -d -print

To find all files containing a particular string
$ find . -name "*" -exec grep "string" {} \; -print

To find all files that are greater than "n" bytes and have not been accessed for more than "x" days,
$ find . -type f -size +nc -atime +x
For example, to find a file greater than 800 bytes and not accessed for more than 10 days, type
$ find . -type f -size +800c -atime +10
The c indicates that the file size is in bytes.

Grep can be used in many different ways. It is fast and powerful and an invaluable tool.grep
searches for a pattern within a file and prints it out to
standard output. You can also redirect the output to a file.
grep supports the following options (from the man pages):

OPTIONS

     The following options are supported for  both  /usr/bin/grep

     and /usr/xpg4/bin/grep:



     -b       Precedes 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       Prints only a count of the lines that  contain  the

              pattern.

     -h       Prevents the name of the file containing the match-

              ing  line  from  being appended to that line.  Used

              when searching multiple files.

     -i       Ignores upper/lower case  distinction  during  com-

              parisons.

     -l       Prints 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       Precedes each line by its line number in  the  file

              (first line is 1).

     -s       Suppresses  error  messages  about  nonexistent  or
              unreadable files.
     -v       Prints all lines except those that contain the pattern.

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

The simplest form of grep is to search for a pattern in a file.
$ grep pattern filename

$ grep -i -n  pattern filename
will match all lines within a file along with the line number that contains pattern(case ignored).

grep has an exit status of 0 for success and 1 for failure.Type

$ echo $?

immediately after grep to retrieve the exit status (bash) or

$ echo $status
in csh

The output of other commands can be piped to grep.
$ ps -ef |grep root > grep_output
will redirect the output to the file grep_output(list of all processes on the system that contain root)
$ ls -l |grep '^d' >> grep_output
will append the output to the file grep_output(list of all directories(all lines beginning with letter d))
$ grep '^pattern$' filename
will print all lines matching only pattern
$ grep '^pattern'
will print all lines that contain pattern.

Posted at 12:57PM Apr 18, 2007 by Jyothi Srinath in Sun  |  Comments[5]