You can search a file for a specific text pattern using the Global Regular Expression Parser command (grep). You can use the grep command to search multiple files simultaneously. You must specify the pattern you want the grep command to search for, as well as one or more filenames on which the grep command can perform the search. The following example shows the grep command searching for the word "text" in the files file1 and file2. The search results display on screen.
Mabel~:$ grep text file1 file2
file1:This file contains text.
file1:You can highlight text using bold or italics.
file2:This file also contains text.
file2:Search for text and you can find it.
You can combine the grep command with other commands using pipes. For example, you can list files in your working directory and then use grep to search the list and return only filenames which contain a one. For information about combining commands, see "Combining commands with pipes."
Mabel~:$ ls | grep 1
file1
file12
file14
You can include wildcards in a search. For information about wildcards, see "Understanding wildcards." You can also specify command options with grep. For a list of available command options and other ways to use the grep command, see the Manual page for the grep command.
To search a file
1. At the command line, type,
grep [options] <pattern> [filenames...]
2. Press ENTER.
Notes
Do not include the brackets in the command line text. For information about notation conventions for commands, see "Using notation conventions for Linux commands."
The ellipsis indicates that you can search multiple filenames simultaneously; for example, grep [options] <pattern> <file1> <file2> <file3>.
If you use wildcards, enclose them in quotes.
If the file you want to search is not in your working directory, use the absolute path name of the file. For information about absolute and relative path names, see "Understanding Linux commands."