JIYIK CN >

In this tutorial, we will learn grepto ignore case in file names using . But first, let's grepstart with .

Use grepto search each file for a pattern. Patterns lists the patterns separated by newlines, grepoutputting each line that matches a pattern.

When used in shell commands grep, the pattern should usually be quoted. If no files are specified, recursive searches check the working directory, while nonrecursive searches read standard input.

grepSyntax in Linux

grepThe syntax of the command is as follows:

$ grep [OPTIONS] PATTERN [FILE...]

Optional items are shown in square brackets.

• OPTIONS- grepThere are several settings that you can use to customize the way it behaves.
• PATTERNis a pattern you can use to find something.
• FILEare the names of one or more input files.

The user running the command must have read permission on the files being searched.

grepCase sensitivity in Linux

grepThe default behavior of commands is case-sensitivity. Case-sensitivity accepts lowercase letters differently than uppercase letters.

For example, the pattern THANOSdoes not match thanos, , Thanosor ThanoS. The text file looks like this:

$ grep "THANOS" thanos.txt

Output:

THANOS

grepUse -ioption to make it case insensitive

grepThe -p option of the command -ican perform a case-insensitive search. For a case-insensitive search, the search pattern THANOSmatches Thanos, , ThaNosor ThanoS.

$ grep -i "THANOS" thanos.txt

Output:

THANOS
thanos
Thanos
ThanoS

ignore-caseThe -w option is -ia more extended variant of the -p option. Hence, we can use the -d command with ignore-casethe -p option grepfor case-insensitive matching.