15 practical grep command examples in linux : unix

15
PracQcal
Grep
Command
Examples
In
Linux
/
UNIX hZp://www.thegeekstuff.com/2009/03/15-‐pracQcal-‐unix-‐grep...

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15
Prac(cal
Grep
Command
Examples
In
Linux
/
UNIX
by
SathiyaMoorthy
on
March
26,
2009

35 Like 53 Tweet 36

Photo
courtesy
of
Alexôme’s

You
should
get
a
grip
on
the
Linux
grep
command.

This
is
part
of
the
on-‐going
15
Examples
series,
where
15
detailed
examples
will
be
provided
for
a
specific
command
or
funcQonality.

Earlier
we
discussed
15
pracQcal
examples
for
Linux
find
command,

Linux
command
line
history
and
mysqladmin
command.

In
this
arQcle
let
us
review
15
pracQcal
examples
of
Linux
grep
command
that
will
be
very
useful
to
both
newbies
and
experts.

First
create
the
following
demo_file
that
will
be
used
in
the
examples
below
to
demonstrate
grep
command.

$ cat demo_file
THIS LINE IS THE 1ST UPPER CASE LINE IN THIS FILE.

1
of
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Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

this line is the 1st lower case line in this file.
This Line Has All Its First Character Of The Word With Upper Case.

Two lines above this line is empty.
And this is the last line.

1.
Search
for
the
given
string
in
a
single
file

The
basic
usage
of
grep
command
is
to
search
for
a
specific
string
in
the
specified
file
as
shown
below.

Syntax:
grep "literal_string" filename

$ grep "this" demo_file

2.
Checking
for
the
given
string
in
mul(ple
files.

Syntax:
grep "string" FILE_PATTERN

This
is
also
a
basic
usage
of
grep
command.
For
this
example,
let
us
copy
the
demo_file
to
demo_file1.
The
grep
output
will
also
include
the
file
name
in
front
of
the
line
that
matched
the
specific
paZern
as
shown
below.
When
the
Linux
shell
sees
the
meta
character,
it
does
the
expansion
and
gives
all
the
files
as
input
to
grep.

$ cp demo_file demo_file1

$ grep "this" demo_*
demo_file:this line is the 1st lower case line in this file.
demo_file:Two lines above this line is empty.
demo_file:And this is the last line.
demo_file1:this line is the 1st lower case line in this file.
demo_file1:Two lines above this line is empty.
demo_file1:And this is the last line.

3.
Case
insensi(ve
search
using
grep
-‐i

Syntax:
grep -i "string" FILE

This
is
also
a
basic
usage
of
the
grep.
This
searches
for
the
given
string/paZern
case
insensiQvely.
So
it
matches
all
the
words
such
as
“the”,
“THE”
and
“ The”
case
insensiQvely
as
shown
below.

$ grep -i "the" demo_file

4.
Match
regular
expression
in
files

Syntax:
grep "REGEX" filename

This
is
a
very
powerful
feature,
if
you
can
use
use
regular
expression
effecQvely.
In
the
following
example,
it
searches
for
all
the
paZern
that
starts
with
“lines”
and
ends
with
“empty”
with
anything
in-‐between.
i.e
To
search
“lines[anything
in-‐between]empty”
in
the

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15
PracQcal
Grep
Command
Examples
In
Linux
/

demo_file.

$ grep "lines.*empty" demo_file

From
documentaQon
of
grep:
A
regular
expression
may
be
followed
by
one
of
several
repeQQon
operators:

?
The
preceding
item
is
opQonal
and
matched
at
most
once.
*
The
preceding
item
will
be
matched
zero
or
more
Qmes.
+
The
preceding
item
will
be
matched
one
or
more
Qmes.
{n}
The
preceding
item
is
matched
exactly
n
Qmes.
{n,}
The
preceding
item
is
matched
n
or
more
Qmes.
{,m}
The
preceding
item
is
matched
at
most
m
Qmes.
{n,m}
The
preceding
item
is
matched
at
least
n
Qmes,
but
not
more
than
m
Qmes.

5.
Checking
for
full
words,
not
for
sub-‐strings
using
grep
-‐w

If
you
want
to
search
for
a
word,
and
to
avoid
it
to
match
the
substrings
use
-‐w
opQon.
Just
doing
out
a
normal
search
will
show
out
all
the
lines.

The
following
example
is
the
regular
grep
where
it
is
searching
for
“is”.
When
you
search
for
“is”,
without
any
opQon
it
will
show
out
“is”,
“his”,
“this”
and
everything
which
has
the
substring
“is”.

$ grep -i "is" demo_file

The
following
example
is
the
WORD
grep
where
it
is
searching
only
for
the
word
“is”.
Please
note
that
this
output
does
not
contain
the
line
“This
Line
Has
All
Its
First
Character
Of
The
Word
With
Upper
Case”,
even
though
“is”
is
there
in
the
“ This”,
as
the
following
is
looking
only
for
the
word
“is”
and
not
for
“this”.

$ grep -iw "is" demo_file

6.
Displaying
lines
before/aQer/around
the
match
using
grep
-‐A,
-‐B
and
-‐C

When
doing
a
grep
on
a
huge
file,
it
may
be
useful
to
see
some
lines
aoer
the
match.
You
might
feel
handy
if
grep
can
show
you
not
only
the
matching
lines
but
also
the
lines
aoer/before/around
the
match.

Please
create
the
following
demo_text
file
for
this
example.

$ cat demo_text
4. Vim Word Navigation

You may want to do several navigation in relation to the words, such as:

* e - go to the end of the current word.
* E - go to the end of the current WORD.
* b - go to the previous (before) word.
* B - go to the previous (before) WORD.
* w - go to the next word.
* W - go to the next WORD.

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15
PracQcal
Grep
Command
Examples
In
Linux
/

WORD - WORD consists of a sequence of non-blank characters, separated with white space.
word - word consists of a sequence of letters, digits and underscores.

Example to show the difference between WORD and word

* 192.168.1.1 - single WORD
* 192.168.1.1 - seven words.

6.1
Display
N
lines
aQer
match

-‐A
is
the
opQon
which
prints
the
specified
N
lines
aoer
the
match
as
shown
below.

Syntax:
grep -A <N> "string" FILENAME

The
following
example
prints
the
matched
line,
along
with
the
3
lines
aoer
it.

$ grep -A 3 -i "example" demo_text

* 192.168.1.1 - single WORD
* 192.168.1.1 - seven words.

6.2
Display
N
lines
before
match

-‐B
is
the
opQon
which
prints
the
specified
N
lines
before
the
match.

Syntax:
grep -B <N> "string" FILENAME

When
you
had
opQon
to
show
the
N
lines
aoer
match,
you
have
the
-‐B
opQon
for
the
opposite.

$ grep -B 2 "single WORD" demo_text

* 192.168.1.1 - single WORD

6.3
Display
N
lines
around
match

-‐C
is
the
opQon
which
prints
the
specified
N
lines
before
the
match.
In
some
occasion
you
might
want
the
match
to
be
appeared
with
the
lines
from
both
the
side.
This
opQons
shows
N
lines
in
both
the
side(before
&
aoer)
of
match.

$ grep -C 2 "Example" demo_text


* 192.168.1.1 - single WORD

7.
Highligh(ng
the
search
using
GREP_OPTIONS

As
grep
prints
out
lines
from
the
file
by
the
paZern
/
string
you
had
given,
if
you
wanted
it
to
highlight
which
part
matches
the
line,
then
you
need
to
follow
the
following
way.

When
you
do
the
following
export
you
will
get
the
highlighQng
of
the
matched
searches.
In
the
following
example,
it
will
highlight
all
the
this
when
you
set
the
GREP_OPTIONS
environment
variable
as
shown
below.

4
of
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Apr
12
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pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

$ export GREP_OPTIONS='--color=auto' GREP_COLOR='100;8'

$ grep this demo_file

8.
Searching
in
all
files
recursively
using
grep
-‐r

When
you
want
to
search
in
all
the
files
under
the
current
directory
and
its
sub
directory.
-‐r
opQon
is
the
one
which
you
need
to
use.
The
following
example
will
look
for
the
string
“ramesh”
in
all
the
files
in
the
current
directory
and
all
it’s
subdirectory.

$ grep -r "ramesh" *

9.
Invert
match
using
grep
-‐v

You
had
different
opQons
to
show
the
lines
matched,
to
show
the
lines
before
match,
and
to
show
the
lines
aoer
match,
and
to
highlight
match.
So
definitely
You’d
also
want
the
opQon
-‐v
to
do
invert
match.

When
you
want
to
display
the
lines
which
does
not
matches
the
given
string/paZern,
use
the
opQon
-‐v
as
shown
below.
This
example
will
display
all
the
lines
that
did
not
match
the
word
“go”.

$ grep -v "go" demo_text
4. Vim Word Navigation

You may want to do several navigation in relation to the words, such as:

WORD - WORD consists of a sequence of non-blank characters, separated with white space.


* 192.168.1.1 - single WORD
* 192.168.1.1 - seven words.

10.
display
the
lines
which
does
not
matches
all
the
given
pa]ern.

Syntax:
grep -v -e "pattern" -e "pattern"

$ cat test-file.txt
a
b
c
d

$ grep -v -e "a" -e "b" -e "c" test-file.txt
d

11.
Coun(ng
the
number
of
matches
using
grep
-‐c

When
you
want
to
count
that
how
many
lines
matches
the
given
paZern/string,
then
use
the
opQon
-‐c.

Syntax:
grep -c "pattern" filename

$ grep -c "go" demo_text
6

5
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12
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15
PracQcal
Grep
Command
Examples
In
Linux
/

When
you
want
do
find
out
how
many
lines
matches
the
paZern

$ grep -c this demo_file
3

When
you
want
do
find
out
how
many
lines
that
does
not
match
the
paZern

$ grep -v -c this demo_file
4

12.
Display
only
the
file
names
which
matches
the
given
pa]ern
using
grep
-‐l

If
you
want
the
grep
to
show
out
only
the
file
names
which
matched
the
given
paZern,
use
the
-‐l
(lower-‐case
L)
opQon.

When
you
give
mulQple
files
to
the
grep
as
input,
it
displays
the
names
of
file
which
contains
the
text
that
matches
the
paZern,
will
be
very
handy
when
you
try
to
find
some
notes
in
your
whole
directory
structure.

$ grep -l this demo_*
demo_file
demo_file1

13.
Show
only
the
matched
string

By
default
grep
will
show
the
line
which
matches
the
given
paZern/string,
but
if
you
want
the
grep
to
show
out
only
the
matched
string
of
the
paZern
then
use
the
-‐o
opQon.

It
might
not
be
that
much
useful
when
you
give
the
string
straight
forward.
But
it
becomes
very
useful
when
you
give
a
regex
paZern
and
trying
to
see
what
it
matches
as

$ grep -o "is.*line" demo_file
is line is the 1st lower case line
is line
is is the last line

14.
Show
the
posi(on
of
match
in
the
line

When
you
want
grep
to
show
the
posiQon
where
it
matches
the
paZern
in
the
file,
use
the
following
opQons
as

Syntax:
grep -o -b "pattern" file

$ cat temp-file.txt
12345
12345

$ grep -o -b "3" temp-file.txt
2:3
8:3

Note:
The
output
of
the
grep
command
above
is
not
the
posiQon
in
the
line,
it
is
byte
offset
of
the
whole
file.

15.
Show
line
number
while
displaying
the
output
using
grep
-‐n

To
show
the
line
number
of
file
with
the
line
matched.
It
does
1-‐based
line
numbering
for
each
file.
Use
-‐n
opQon
to
uQlize
this
feature.

$ grep -n "go" demo_text
5: * e - go to the end of the current word.
6: * E - go to the end of the current WORD.

6
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

7: * b - go to the previous (before) word.
8: * B - go to the previous (before) WORD.
9: * w - go to the next word.
10: * W - go to the next WORD.

Addi(onal
Grep
Tutorials

7
Linux
Grep
OR,
Grep
AND,
Grep
NOT
Operator
Examples
Regular
Expressions
in
Grep
Command
with
10
Examples
–
Part
I
Advanced
Regular
Expressions
in
Grep
Command
with
10
Examples
–
Part
II
Search
in
a
*.bz2
file
using
bzgrep,
and
*.gz
file
using
zgrep

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examples
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Examples
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Line
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Command:
15
PracQcal
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Tags:
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{
71
comments…
read
them
below
or
add
one
}

1
Joao
Trindade
March
28,
2009
at
3:54
am

7
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

You
have
a
small
glitch:
>>
4.
Match
regular
expression
in
files
using
grep
-‐i

Don’t
you
mean:
4.
Match
regular
expression
in
files
using
grep
-‐e

The
rest
of
the
post
is
great.

2
Ramesh
March
29,
2009
at
12:16
am

Joao,

Thanks
for
poinQng
it
out.
I
have
corrected
it.
Also,
we
can
do
REGEX
without
the
opQon
-‐e
as
shown
in
the
example
#4.

From
Man
Pages:

SYNOPSIS
grep [options] PATTERN [FILE...]
grep [options] [-e PATTERN | -f FILE] [FILE...]

-e PATTERN, --regexp=PATTERN
Use PATTERN as the pattern; useful to protect patterns beginning with -.

3
dragon
March
31,
2009
at
11:26
pm

Hi:

FYI,
Qp
14
will
be
2:3
8:3
on
Ubuntu
system.
(including
the
n
character
I
guess

4
Ramesh
March
31,
2009
at
11:44
pm

Dragon,

Thanks
for
poinQng
it
out.
I’ve
corrected
it.

5
Francesco
Talamona
April
26,
2009
at
2:48
am

I
find
very
useful
the
following
command,
when
you
have
to
deal
with
a
very
lengthy
configuraQon
file
full
of
comments:

grep
-‐v
-‐E
‘^#|^$’
/etc/squid/squid.conf

It
skips
every
line
beginning
with
an
hash
(#)
or
empty,
so
you
can
see
at
a
glance
the
15
lines
edited
out
of
a
+4400
lines
text
file.

BTW
interesQng
topics,
great
posts…

6
albar
May
7,
2009
at
7:51
pm

help
me
how
to
bzgrep
:
^C02
but
^C
is
count
as
one
special
character,
in
this
word:
data1^C02data2

thank’s

7
Ramesh
Natarajan
May
8,
2009
at
5:51
pm

@Francesco
Talamona,

8
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

Thanks
a
lot
for
sharing
your
grep
command
example.
Yes.
all
those
empty
lines
and
comment
lines
can
get
very
annoying
when
you
do
grep.
So,
it
is
an
excellent
idea
to
hide
them
in
the
grep
output
with
your
examples.

8
sasikala
May
11,
2009
at
9:41
pm

@albar,

try
like
this
grep
‘^C02ʹ′

9
albar
May
12,
2009
at
1:18
am

@sasikala
,
i
do
have
try
that
too,
but
sQll
got
nothing,
but
it
works
when
^
and
C
count
as
two
character

thank’s

10
SathiyaMoorthy
May
12,
2009
at
4:33
am

@albar

You
should
type
^C
as
ctrl-‐v
+
ctrl-‐c
in
grep
as
single
character
as
$
grep
^C02
ﬁle

Dont
escape,
dont
type
it
as
^
C
as
two
characters.
Hope
this
helps.

11
albar
May
12,
2009
at
8:59
pm

@sathiya,
god
bless
u
all
it
work’s
thanks

12
Manish
Patel
May
21,
2009
at
7:00
pm

Hi

I
am
trying
to
exclude
the
last
word
of
all
the
line
like
sync.php,
uploads.php,
backup.php

File
text
include
as
below

/usr/home/htdocs/drag-‐and-‐drop/htdocs.php
/usr/home//htdocs/sms/publish/pages/sync.php
/usr/home/htdocs/track/backup.php
/usr/home/htdocs/smstest/smstest.php
/usr/home/htdocs/uploads.php
/usr/home/htdocs/017/backup.php

How
can
I
achieve
that
using
grep
or
sed
or
awk

Also
how
I
can
use
“*”
wildcard
in
sed
command
like
to
replace
*.php
to
*.txt
or
any
other
extension.

Thank
you
in
advance.

Manish

13
Francesco
Talamona
May
21,
2009
at
10:36
pm

Are
you
restricted
to
sed
or
awk?

1)
dirname
‘/usr/home/htdocs/drag-‐and-‐drop/htdocs.php’

9
of
22 18
Apr
12
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pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

/usr/home/htdocs/drag-‐and-‐drop

2)
rename
does
what
you
want

14
Manish
Patel
May
24,
2009
at
6:55
pm

Hi,

Those
lines
are
the
contents
of
the
text
file
and
I
don’t
want
to
change
the
actual
directory
or
the
file
on
server.
I
want
to
change
the
contents
of
the
file
where
all
file
file
names
ending
at
the
line
should
be
removed.
So
the
final
file
contents
should
look
like
this

cat
filecontenet.txt
/usr/home/htdocs/drag-‐and-‐drop/
/usr/home//htdocs/sms/publish/pages/
/usr/home/htdocs/track/
/usr/home/htdocs/smstest/
/usr/home/htdocs/
/usr/home/htdocs/

I
think
rename
would
not
help
here
in
ediQng
file
contents.

Thank
you
Manish

15
SathiyaMoorthy
May
24,
2009
at
11:43
pm

rev
filecontenet.txt
|
cut
-‐d’/’
-‐f2-‐
|
rev

rev
filecontenet.txt
–>
reverses
the
file
and
pipes
to
cut
command.
cut
-‐d’/’
-‐f2-‐
–>
cuts
off
the
first
field
(
cuts
off
last
field,
as
it
is
reversed
).
rev
–>
prints
the
output
given
order.

16
P0B0T
May
26,
2009
at
11:36
pm

Manish,

I
believe
you’re
looking
for
the
following

sed
-‐e
‘s/.php$//’
filecontenet.txt

17
P0B0T
May
26,
2009
at
11:39
pm

Sorry,
didn’t
read
your
requirement
carefully.

Try
this:

sed
-‐e
‘s//[^/]*.php$///’
filecontenet.txt

18
Manish
Patel
June
5,
2009
at
5:31
pm

Hi

Thank
you
to
Sathiya
Moorthy
and
P0B0T.

Both
soluQon
worked
very
nicely
for
me.

P0B0T
can
you
explain
how
your
command
works
for
each
defined
opQon
’s//[^/]*.php$///’

Thank
you
Manish

10
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22 18
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15
PracQcal
Grep
Command
Examples
In
Linux
/

19
mano
June
10,
2009
at
3:00
am

The
above
info
on
grep
is
really
great.
I
want
to
search
for
a
string
in
all
the
files
in
the
directory
and
add
a
$
symbol
at
the
start
of
the
searched
line
and
save
in
the
same
file.

20
SathiyaMoorthy
June
18,
2009
at
10:49
pm

@mano
More
than
using
grep
for
this
requirement,
you
can
use
sed
which
is:
sed
-‐i
‘s/.*abc.*/$&/’
*

-‐i
:
edit
the
input
file.
s///
:
subsQtute
the
matched
paZern
with
the
replacement
string.
/.*abc.*/
:
match
the
string
abc
/$&/
:
Replace
with
$
followed
by
matched
string.
*
:
all
the
files
in
the
current
directory.

This
is
one
way
of
saQsfying
your
requirement,
there
may
be
other
efficient
ways.

Hope
this
helps.

21
mano
June
19,
2009
at
12:17
am

Hi
SathiaMoorthy,
Thank
u
so
much.
it
works
fine.
If
I
need
to
search
for
files
in
all
subdirectories,
how
should
this
“sed”
command
modified?

Thanks
in
advance.

mano

22
SathiyaMoorthy
June
27,
2009
at
12:05
am

@mano
ModificaQon
in
sed
command
is
not
needed.

To
search
for
all
files
in
the
subdirectory.
find
.
-‐type
f

Execute
the
command
on
all
those
files
with
-‐exec.
find
.
-‐type
f
-‐exec
sed
-‐i
‘s/.*abc.*/#&/’
{}
;

But
think
twice
before
execuQng
this
command,
because
it
will
recursively
edit
all
the
files.
Taking
backup
before
execuQng
this
command
is
wise.

Refer
the
earlier
arQcle
linux
find
command
examples.

23
Vidya
July
1,
2009
at
2:59
am

Hi,

I
want
to
grep
next
3
words
in
a
line
from
the
matching
criteria
word..
like
if
the
line
is

This
is
-‐g
gateway
-‐e
enterprise
-‐s
server

Then
I
want
to
grep
“-‐g
gateway
-‐e
enterprise”
from
the
line

Can
you
please
help
me
in
this
case.
Here
gateway
and
enterprise
value
can
be
anything
so
need
to
grep
next
3
words
starQng
form
“-‐g”

24
SathiyaMoorthy
July
1,
2009
at
5:58
am

11
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22 18
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12
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15
PracQcal
Grep
Command
Examples
In
Linux
/

@Vidhya

$
grep
-‐o
-‐E
—
“-‐g
w+
-‐e
w+”
FILENAME
-‐g
gateway
-‐e
enterprise

ExplanaQon
of
the
above
command.,

-‐o
:
only
matching
(
point
13.
)
-‐E
:
extended
regexp
—
:
indicate
end
of
opQons
w+
:
word

25
Vidya
July
1,
2009
at
9:00
am

Hi
Sathiya,
Its
not
working.
It
says
grep:
illegal
opQon
—
o
grep:
illegal
opQon
—
E
Usage:
grep
-‐hblcnsviw
paZern
file
.
.
.

I
am
working
on
Solaris
and
se…ng
shell
as
bash.

26
Amit
Agarwal
September
21,
2009
at
6:18
am

grep
version
on
solaris
is
liZle
older
and
as
man
would
show
you
all
these
opQons
are
not
available,
so
you
can
try
ack
(standalone)
version
which
is
very
powerful
and
requires
only
perl
to
be
installed.

27
learner
October
7,
2009
at
5:31
am

Hi,
How
to
use
grep
to
find
lines
containing
mulQple
strings
ex:
line1:Today
is
oct
7,
wednesday.
not
8th
line2:
This
is
not
summer.
line3:
when
is
summer?
I
want
to
return
line2
containing
strings
“not”
and
“summer”
both.

Thank
You.

28
SathiyaMoorthy
October
7,
2009
at
10:41
am

@learner

There
are
several
ways
possible,
use
the
one
which
you
find
as
appropriate.

$ grep "not.*summer" file1
line2: This is not summer.

$ grep "not" file1 | grep "summer"
line2: This is not summer.

29
learner
October
7,
2009
at
10:56
pm

@SathiyaMoorthy

Thank
You
for
your
very
quick
reply.

My
quesQon
was
not
piping
and
hard
coding
every
string
,
as
i
menQoned
mulQple
strings,
i
was
looking
for
something
in
likes
of
grep
-‐F
‘string1
string2
string3

12
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22 18
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12
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pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

string4
…..
stringn’
filename
which
returns
single
occurrence
of
something
like
either
string1
,string2,..
stringn
or
all
..,
what
i
wanted
was
only
string1
and
string2
and
…….
stringn
begin
returned.
[please
note
that
i
will
be
provided
with
strings
as
newline
separated
strings
,which
i
don't
want
to
parse
again
and
i
have
constraint
of
using
grep
only]

Thank
You.

30
Ashish
December
1,
2009
at
4:07
pm

Hi,

I
need
to
sthing
like
this
I
have
a
file
containing
400
domainId
values
seprated
by
new
line
ex.
domain.txt
domain1
domain2
domain3…

I
have
a
script
that
takes
each
domain
and
calls
an
api
that
returns
me
an
xml.
like
this
for
each
domain
val1
domain1
val2
val3
val4
XXX
val1

now
i
want
to
spit
out
the
domain
name
in
a
file
that
does
not
matches
domainid
value
XXX.

how
can
i
do
it
using
grep
TIA

31
Ashish
December
1,
2009
at
4:16
pm

Hi,

I
need
to
sthing
like
this
I
have
a
file
containing
400
domainId
values
seprated
by
new
line
ex.
domain.txt
domain1
domain2
domain3…

I
have
a
script
that
takes
each
domain
and
calls
an
api
that
returns
me
an
xml.
like
this
for
each
domain

<tag1>val1</tag1>
<domain>domain1</domain>
<tag2>val2</tag2>
<tag3>val3</tag3>
<tag4>val4</tag4>
<domainid>XXX</domainid>
<tag5>val1</tag5>

now
i
want
to
spit
out
the
domain
name
in
a
file
that
does
not
matches
domainid
value
XXX.

13
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

how
can
i
do
it
using
grep
TIA

32
Varun
December
17,
2009
at
7:16
am

Hi,
The
opQons
menQoned
in
point
6
for
displaying
the
context
with
A,
B,
&
C
does
not
seem
to
work
on
Solaris
10
with
both
grep
&
egrep

Is
there
a
version
of
this
grep
available
for
Solaris?

Thank
you,
Varun.

33
Jawn
Hewz
December
21,
2009
at
7:54
pm

Does
the
-‐b
(byte
offset)
work
when
greping
binary
files?
I
do
not
get
an
offset
returned
when
I
grep
a
binary
file,
but
I
do
when
using
a
text
file.
I
am
using
grep
under
Cygwin.

34
fety
January
11,
2010
at
3:32
am

thanks
very
much
for
this
tutorial.
it
is
very
helpful..

35
eMancu
January
24,
2010
at
12:49
pm

Awsome
tutorial!
I’m
reading
all
your
blog,
its
amazing!

36
Raghu
Baba
January
30,
2010
at
4:44
am

Hai..
I
want
to
Parse
my
file
..
Word
to
Excel
..
so
tell
me
some
grep
&
cut
commands…

37
Jeff
Floyd
February
1,
2010
at
6:54
pm

Whats
the
difference
between
$
grep
-‐c
ill
memo
and
$
grep
-‐n
ill
memo?

38
joeq
February
4,
2010
at
3:57
am

hi
i
got
1
problem…how
can
i
find
a
numbers
like
99,000,000.95
in
my
server
database
using
unix
command..
tq

39
abhishek
February
21,
2010
at
4:31
am

content
was
very
useful

40
Anonymous
March
8,
2010
at
4:26
am

Hi,

Those
lines
are
the
contents
of
the
text
file
and
I
don’t
want
to
change
the
actual
directory
or
the
file
on
server.
I
want
to
change
the
contents
of
the
file
where
all
file
file
names
ending
at
the
line
should
be
removed.
So
the
final
file
contents
should
look
like
this

cat
filecontenet.txt
/usr/home/htdocs/drag-‐and-‐drop/
/usr/home//htdocs/sms/publish/pages/
/usr/home/htdocs/track/
/usr/home/htdocs/smstest/
/usr/home/htdocs/
/usr/home/htdocs/

14
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

I
think
rename
would
not
help
here
in
ediQng
file
contents.

for
this
quesQon
,
awk
really
helpful
with
single
line
command

go
to
the
current
directory
ls
-‐l
|
grep
-‐v
^d
|
awk
‘{print
$9}’
>
new.txt

$9
—
is
the
last
filed
which
is
filename
only
when
u
list
with
opQon
ls
-‐l
,
new.txt
contains
only
the
filenames
which
you
wnated
to
filter
out

41
skipper
March
26,
2010
at
5:54
am

nice
arQcle

42
VIKAS
April
4,
2010
at
7:23
pm

Excellent
stuff,
just
loved
grep
-‐A,B,C
opQons
and
grep
-‐o
“xxxx.*yyyy”
kinda
commands.

This
will
help
me
a
lot,
I
used
awk
more
in
my
shell
scripts,
But
I
have
got
a
new
friend
“grep”
for
some
selecQve
prinQng

43
Sam
April
17,
2010
at
3:35
am

I
have
just
finish
reading
this
wonderful
arQcle.
Let
me
answer
this:
Whats
the
difference
between
$
grep
-‐c
ill
memo
and
$
grep
-‐n
ill
memo?
grep
-‐c
return
the
number
lines
that
matched
ill
in
memo.
grep
-‐n
return
the
matched
lines
with
line-‐number
as
prefix.

44
Chong
April
20,
2010
at
3:05
am

how
to
grep
a
statement
contain
‘*’
from
a
file
at
the
same
Qme
to
match
the
first
character
too.

example
the
statement
in
filename
profile.txt
:-‐

“Mary
stay
at
uZana*istana
with
her
grandmum”

current
grep
statement
:-‐
grep
“^Mary
stay
at
uZana*istana”
profile.txt

result:
no
row
matched
the
grep
statement
because
of
*
How
to
use
grep
command
for
the
combine
condiQon
of
statement
with
*
and
match
the
front
word?

45
vm
April
30,
2010
at
8:24
pm

In
bash
script
without
using
perl,
how
i
can
grep
a
number
from
a
file
if
there
exists
a
number
greater
than
80
in
that
file.

46
palash
June
13,
2010
at
12:14
pm

grep
-‐c
“paZern”
filename
returns
the
number
of
lines
that
matches
the
paZern,
even
if
the
paZern
occurred
for
more
than
one
Qme
in
any
line.
Is
there
any
opQon
to
know
how
many
Qmes
the
paZern
matched
in
a
file?

47
mathan
June
20,
2010
at
10:21
am

HI,
I
am
new
to
linux…
can
you
tell
me
how
to
exit
from
grep
command….
mistakenly
i
type
grep
filename

But
it’s
nothing
shown….
pls
looking
for
quick
reply…

48
SathiyaMoorthy
July
4,
2010
at
7:20
am

15
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22 18
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pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

@mathan

There
is
nothing
like
exiQng
from
grep.

First
argument
to
grep
is
taken
as
PATTERN,
not
as
filename.
So
as
far
as
i
understand
it
is
waiQng
for
input
to
match.
So
just
exit
from
it
using
CTRL+D.

49
Ross
HuggeZ
September
16,
2010
at
5:04
am

Nice
arQcle.
Thanks.

50
ec
October
6,
2010
at
6:14
pm

Hi
to
all,
I
just
started
to
learn
linux
a
month
ago
Can
I
extract
2
to
6
leZer
words
from
a
text
file
using
one
grep
command
only!
To
menQon
that
each
word
is
on
its
own
line
what’s
the
grep
command
to
do
this
job?
I
tried
any
combinaQon
of
grep
and
not
the
result
which
I
am
looking
for

51
Lou
February
24,
2011
at
1:16
pm

Is
there
a
way
to
grep
for
a
word
on
in
a
file
and
return
that
line
plus
the
next?

52
Francesco
Talamona
February
26,
2011
at
3:33
am

@
Lou:

cat
tes‰ile.txt
first
line
matching
line
following
line
ending
line

grep
matching
-‐B
1
tes‰ile.txt
first
line
matching
line

53
abhishek
kumar
April
19,
2011
at
12:53
pm

really
to
nice
and
too
simple
to
understand,

thats
great

thank
you

54
Nikita
April
21,
2011
at
12:06
pm

PLEASE
HELP
ON
QUESTION
B.

You
are
searching
a
file
for
lines
that
contain
US
state
abbreviaQons
in
parentheses.
e.g.:
(ma),(NH),(Ky),
etc.
So
you
decide
to
match
any
line
containing
(
)
with
exactly
two
characters
(not
leZers)
in
between.
A)
What
grep
will
get
this
done?

My
Answer—>
grep
‘([a-‐zA-‐Z][A-‐Za-‐z])’
file

You
now
noQce
that
some
of
the
lines
that
the
grep
from
part
A
matched
contain
the
the
string
(expired).
You
want
to
eliminate
these
lines
from
your
output,
so
you
decide
to
pipe
your
output
to
another
grep.
B)
What
will
the
new
command
be?
(both
greps
with
the
pipe)

My
Answer
—>
grep
–v
grep
|
grep
‘([a-‐zA-‐Z]
[A-‐Za-‐z])’
——-‐>
PLEASE
HELP!

16
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22 18
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pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

55
Francesco
Talamona
April
22,
2011
at
12:44
pm

@Nikita:
One
step
is
enough:
egrep
‘([a-‐zA-‐Z]{2})’
file

56
suprabhat
April
27,
2011
at
3:26
am

How
to
display
all
lines
that
have
less
than
9
character
in
a
file

57
Paul
May
16,
2011
at
3:09
pm

I’m
new
to
linux;
was
wondering
what
does
#
aoer
the
grep
command
accomplish,
as
shown
in
the
example
below?

grep
#
input*.txt
|
awk
‘{print
$4}’
|
sort
|
uniq
>
output.txt

thank
you

58
Dinesh
May
17,
2011
at
4:03
pm

For
a
given
patern
like
Fri
Nov
26
16:04:52
2010
I
want
to
grep
for
all
the
lines
in
a
file
having
the
above
format.
But
I
have
all
the
values
except
for
the
Qme,
that
is
“16:04:52
”
,
the
data
I
have
is
“Fri
Nov
26
2010
”
.
The
file
is
having
5
years
of
date
with
the
Qmestamp
as
specified
above.
Please
let
me
know
How
shall
I
grep
the
file
to
get
all
the
lines
on
the
date
“Fri
Nov
26
2010
”
.

thanks

59
shyam
May
29,
2011
at
10:45
pm

i
have
a
doubt
here
i
tried
to
look
at
output
of
cmd

grep
“[Â-‐Z]”
file.txt

this
is
showing
all
characters
excluding
capital
leZer
what
does
this
command
actually
do

60
shivaraj
PaQl
July
25,
2011
at
11:14
am

HI
i
have
a
file
with
this
values
100
first
line
101
second
line
101
102
102
109
now
i
need
a
script
that
can
take
two
lines
and
find
which
is
greatest

61
sudheer
September
10,
2011
at
8:32
pm

1)
Use
grep
(or
awk)
to
output
all
lines
in
a
given
file
which
contain
employee
ID
numbers.
Assume
that
each
employee
ID
number
consists
of
1-‐4
digits
followed
by
two
leZers:
the
first
is
either
a
W
or
a
S
and
the
second
is
either
a
C
or
a
T.
ID
numbers
never
start
with
0s.
Further
assume
that
an
employee
ID
is
always
proceeded
by
some
type
of
white
space
–
tab,
blank,
new
line
etc.
However,
there
might
be
characters
aoer
it,
for
example
punctuaQon.
What
to
turn
in:
Turn
in
three
things:

a.
A
file
with
the
regular
expression
which
can
directly
be
used
by
grep
(or
awk)

b.
A
text
file
which
you
used
to
test
your
regular
expression.
Make
sure
that
you
include
valid
and
‘invalid’
employee
IDs,
have
them
at
the
beginning
and
the
end
of
lines,
sentences,
etc.

17
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

c.
A
second
document
which
re-‐writes
the
regular
expression
in
a
more
human-‐readable
form
and
explains
the
purpose
of
the
different
components
of
the
regular
expression.
Also
include
a
short
explanaQon
of
your
test
cases.

2)
Use
grep
(or
awk)
to
output
all
the
lines
in
a
given
file
which
contain
a
decimal
number
(e.g.
a
number
which
includes
a
decimal
point).
Decimal
numbers
do
not
have
leading
zeros
but
they
might
have
trailing
zeros.
Assume
the
number
is
always
surrounded
by
white
space.

What
to
turn
in:
The
same
three
things
as
above
(except,
of
course,
for
this
problem).

3)
Write
a
regular
expression
for
the
valid
idenQfiers
in
Java.
You
are
allowed
to
use
‘shortcuts’,
but
need
to
make
sure
that
you
specify
exactly
what
they
are
(e.g.
if
you
use
digit
specify
that
that
means
0,
1,
2,
3,
….9.)

62
Dinesh
September
22,
2011
at
12:43
pm

Paul

grep
#
input*.txt
|
awk
‘{print
$4}’
|
sort
|
uniq
>
output.txt

Since
#
is
a
special
character,we
are
treaQng
#
as
#
by
pu…ng
backslash
infront
of
that.
Noe
Greap
searches
for
paZern
#
in
a
list
of
file
starQng
as
input
and
nding
a
txt
and
then
awk
prints
the
4th
field
and
sort
is
doing
sorQng
the
4th
field
returns
from
awk
and
unis
is
doing
uniq
operaQon.

63
Dinesh
September
22,
2011
at
12:45
pm

Shyam

grep
“[Â-‐Z]”
file.txt

Grep
will
print
the
lines
that
does
not
start
with
CAPTIAL
LETTERS.

Using
^
inside
the
[]
will
do
the
work
opposite
to
the
paZern
what
you
have
been
searching
for
…

64
haydarekarrar
December
23,
2011
at
4:29
am

Just
a
minor
thing
the
last
result
line
is
removed
in
the
example
above,
this
should
be
the
result:

$
grep
“this”
greptest.txt
this
line
is
the
1st
lower
case
line
in
this
file.
Two
lines
above
this
line
is
empty.
And
this
is
the
last
line.

65
gotham
January
22,
2012
at
4:32
am

awesome.
thanks
a
lot.

66
edward
January
31,
2012
at
2:20
am

For
example
my
data
is
(file.ave)
:

MRR
120101000000
UTC+07
AVE
60
STF
150
ASL
H
150
300
450
600
750
900
TF
0.0149
0.0515
0.1171
F00
-‐67.04
F01
-‐69.27

I
use
grep
as:
grep
-‐r
‘MRR’
*.ave
>
Qme_0101.txt.
In
this
case
all
file
goes
to
Qme_0101.txt,
I
have
many
files
and
I
need
each
output
goes
to
specific
file
name.
Any
idea
?
And
how
to
use
grep
to
take
F00
and
F01
?
If
I
use
grep
-‐r
‘F’
*.ave,
the
first
line
will
be
taken
also
because
of
STF,
Thanks
for
help..

67
shrikant
February
14,
2012
at
10:23
am

18
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

Thank
you

68
chinna
February
19,
2012
at
8:48
am

here
my
quesQon
is
in
a
directory
i
have
10
files.some
files
contains
size
in
kb’s
and
some
files
contains
size
in
mb’s…..i
want
display
the
files
only
which
file
size
is
more
than
1
mb……
could
anybudy
help
to
find
answer
for
this
quesQon….

69
Anderson
Venturini
March
14,
2012
at
6:01
am

Great
post!
It
was
very
useful!
thanks
a
lot!

70
Anonymous
April
9,
2012
at
3:22
pm

To
answer
Chinna…
If
you
have
some
files
showing
M,
and
some
K,
then
your
“ls”
command
is
probably
running
on
a
Linux
box,
and
using
the
“-‐h”
opQon.

The
preferred
method
would
be
NOT
to
use
the
“-‐h”
opQon,
and
let
“ls”
print
file
sizes
in
bytes,
which
means
that
your
script
will
be
able
to
get
the
same
units+detail
for
all
file
sizes
listed.

Then
you
can
use
“awk”
to
filter
out
files
where
$5
(5th
field)
is
over
1Meg,
like
this:

/bin/ls
-‐l
|
awk
‘$5>=2^20ʹ′

If
you
only
want
file
names,
not
‘ls’
style
list,
then
have
awk
give
you
that
part
of
output:
/bin/ls
-‐l
|
awk
‘$5>=2^20{print
$NF}’

Note:
this
does
not
like
file
names
with
spaces…
—-‐
notes
for
Other
posQngs
on
this
thread:
To:
Francesco
Talamona
(who
was
using
“grep”
to
remove
##_comments
from
long
config
files)
grep
-‐v
-‐E
‘^#|^$’
You
may
want
to
remove
comments
that
do
NOT
start
on
the
first
char
of
a
line,
and
‘sed’
is
more
useful
for
that
sed
‘s/#.*$//;/^[
]*$/d’
This
will
remove
comments
from
each
line,
then
discard
the
line
if
blank,
or
only
spaces
remain.
=========
Also,
where
the
-‐B
and
-‐A
opQons
are
described
for
“grep”…
This
is
for
GNU/Linux,
and
not
supported
for
most
Non-‐Linux
boxes.

#–JETS

71
KHEE
April
15,
2012
at
8:39
pm

Hi
expert,

i
am
new
to
unix
env…
try
to
use
certain
command
to
help
me
generate
1
output
file
as
below:

input
file:
A
A/I
0.2
0.3
0.8
B
B/I
0.6
0.8
0.9
C
C
0.8
2.1
6.0

I
just
want
to
grep
all
A
B
C
only,
where
want
to
skip
the
line
which
have
the
number
together.
And
my
output
file
paZern
is
A
B
C
D…etc
(
A,
B,C
all
are
a
word).

19
of
22 18
Apr
12
7:31
pm

15
PracQcal
Grep
Command
Examples
In
Linux
/

mean
i
want
ﬁrst,second
line,
and
skip
3rd
&
4th
lines,
thanks
for
help.

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