grep - what arguments do you usually specify?

Question

My most common grep line is just..

grep -IRl "text" *

However I'm kinda getting tired of retyping this over and over - is there some way I can make an alias command so that those arguments are always enabled?

And, I was wondering what arguments you usually specify for text searching - my two arguments 'R' for recursion, 'I' for not including binary types like jpg/gif, and 'l' for line number seem a bit too minimal. Which arguments do you use?

Answer 1

Check out the GREP_OPTIONS environment variable. More info is in man grep:

GREP_OPTIONS

This variable specifies default options to be placed in front of any explicit options. For example, if GREP_OPTIONS is '--binary-files=without-match --directories=skip', grep behaves as if the two options --binary-files=without-match and --directories=skip had been specified before any explicit options. Option specifications are separated by whitespace. A backslash escapes the next character, so it can be used to specify an option containing whitespace or a backslash.

Answer 2

I also use --color, to color the output, and sometimes -Bn and -An, where n is a number, to show a number of lines before and after the matched lines, thus giving context.

Answer 3

You can add this to your .bashrc:

alias grep="grep -IRl"

Answer 4

I often use -n, which prints the line number of the match in the file. This is particularily useful in conjunction with -H, which prints the name of the file that matched (this defaults to ON for multi-file searches).

So, for example, if call grep -Hn 'foo' * in a directory full of files, I get output similar to this:

foo.txt:34:line that matched that contains foo
foo.txt:51:another line with foo
bar.c:4:int foo;

Answer 5

If find the following quite handy, to search my source tree while ignoring SVN metadata files:

alias grepnosvn="grep -r --exclude-dir=.svn"

Answer 6

is there some way I can make an alias ...

See alias.

Answer 7

Best grep is clean grep.

Example: grep stdio *

Answer 8

I use whatever I need in the given situation. If I need to grep recursively, I use -r. If I need to search cases-insensitively, I use -i.

The only option of grep that I use each time, is --color. But Sinan Taifour already pointed that one out.

Answer 9

I use

grep -i

for case insensitive search

grep -l

to just list the file names

grep -n

To list line numbers of the occurence in the file names

grep -v

To list the files that don't contain the pattern

Answer 10

• -R for recursive searching
• -A 2 and -B 2 to display the 4 lines around the matched-line (2 before, 2 after)
• -i to ignore case

For example:

grep -Ri -A2 -B2 /some/dir somethingtomatch

Answer 11

The only option I specify by default, by using an alias, is using colour to highlight matches:

alias grep='grep --color=auto'

Answer 12

Regarding your first question, other people mentioned GREP_OPTIONS and bash alias.

Yet another way is to use a shell script to run grep with your favorite options.

Create the file ~/bin/mygrep with following contents:

#!/bin/bash
grep -IR1 "$@"

Then you can run

mygrep hello file1 file2

which is effectively same as

grep -IR1 hello file1 file2

When you try out or switch to shells other than bash, such as fish or zsh, your mygrep will be available there too.

You can also make myls, myls2, myrsync, myperl and so on.

Answer 13

grep -Hni

Actually, egrep -Hni. The "e" is for the extended version of grep which supports a more powerful pattern matching language.

The -Hni form is really useful for jumping quickly to matches because it produces the "Emacs format" that is supported by many environments. The format looks like this:

<path>:<line-number>:<column-number>: <match>

An example looks like this:

/some/path/to/a/file:4:6: foo

Sure, -R can be thrown in as well to descend recursively into subdirectories, but I usually use xargs to supply filenames to grep from find:

find . -type f -name '*some-filename-pattern*' -print0 | xargs -0 -n 1 egrep -Hni some-search-pattern

Of course, this can all be packaged into a script (with absolute path names for the executables).

Answer 14

Actually I ended up aliasing 'g' to 'grep -RlI' because those extra arguments can sometimes offset something, example being 'ps aux | grep pidgin' returned ( standard input ) instead of what I wanted. Plus it's less stuff to type. Thanks for all the answers.

Answer 15

Take a look at ack. It is optimized specifically for cases like yours.

grep -IRl "text" *

in ack would be

ack text

By default, ack ignores binary files, version control directories, and many others. It also by default recurses down the directory tree and shows line numbers.

It's a Perl program that you can download and put into your ~/bin directory and you don't have to install anything else, so no need for admin rights. And it runs the same on Windows.