How To Find Files by Content Under UNIX

Post date: Dec 21, 2009 8:54:06 AM

Q. I had written lots of code in C for my school work and saved it as source code under /home/user/c/*.c and *.h. How do I find files by content such as string or words (function name such as main() under UNIX shell prompt?

A. You need to use following tools:

[a] grep command : print lines matching a pattern.

[b] find command: search for files in a directory hierarchy.

grep command to find files by content

Type the command as follows:

grep 'string' *.txt

grep 'main(' *.c

grep '#include<example.h>' *.c

grep 'getChar*' *.c

grep -i 'ultra' *.conf

grep -iR 'ultra' *.conf

Where

-i : Ignore case distinctions in both the PATTERN (match valid, VALID, ValID string) and the input files (math file.c FILE.c FILE.C filename).

-R : Read all files under each directory, recursively

Highlighting searched patterns

You can highlight patterns easily while searching large number of files:

$ grep --color=auto -iR 'getChar();' *.c

Displaying file names and line number for searched patterns

You may also need to display filenames and numbers:

$ grep --color=auto -iRnH 'getChar();' *.c

Where,

-n : Prefix each line of output with the 1-based line number within its input file.

-H Print the file name for each match. This is the default when there is more than one file to search.

$grep --color=auto -nH 'DIR' *

You can also use find command:

$ find . -name "*.c" -print | xargs grep "main("