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Old 01-13-2017, 10:34 AM   #1
chtsalid
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Perform a case-insensitive search for a pattern


Hi guys,

how can I perform the following?

Perform a case-insesitive search for the pattern 'then' in the /etc/profile file and save the result in the /var/tmp/pattern.txt. Make sure that empty lines are not included.

Many thanks!
 
Old 01-13-2017, 10:47 AM   #2
goumba
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Hello and welcome to LQ. Please note the thread you started doesn't meet the minimum threshold that would enable us to help you. We understand that Linux can be intimidating for new members, and we really do want to help. That said, please understand that LQ is not a help desk, customer service line for a product you purchased or willing to do your homework (although we are happy to assist you with specifics, if you show some effort of your own!). We're a 100% volunteer organization that wants to help you help yourself.

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Old 01-13-2017, 12:26 PM   #3
rtmistler
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Firstly show what you have tried so that others can understand your expertise as well as how far along with this effort you are.

Check the arguments available for the grep command, you'll notice a lot of capabilities regarding case sensitivity as well as conditioning the output to a form which you'd like to see.

I'm assuming you have some familiarity with using the grep command in the first place, likely that is an answer about how to find a string or pattern within a file.

Look up input/output redirection for Linux and likely you'll figure out how to save your result.

Can you tell me something special about the /var/tmp directory which you should be paying attention too?

I'm assuming that this poorly phrased request is only part of the puzzle. Best you explain really what you are trying to accomplish entirely so that others can offer suggestions.

As goumba points out, LQ members are not here for fast food ordering of content, instead we're here voluntarily to help you to learn more about Linux.
 
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Old 01-13-2017, 12:58 PM   #4
Habitual
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When is the test?
 
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Old 01-13-2017, 05:09 PM   #5
goumba
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Quote:
Originally Posted by Habitual View Post
When is the test?
Exactly why I highlighted what I did. "Make sure that empty lines are not included" seems to me a homework directive or an order from a superior (likely the former).

The OP showed no work. Very simple using grep, had they bothered to even search the forums as it is a fairly common request (I neglected to highlight that point at well).
 
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Old 01-14-2017, 01:34 AM   #6
chtsalid
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Hi all,

thank you for your input. Here is what I did.

Is this a case sensitive search or should I do something more?

[root@rhcsa1 ~]# grep then /etc/profile
if [ "$2" = "after" ] ; then
if [ -x /usr/bin/id ]; then
if [ -z "$EUID" ]; then
if [ "$EUID" = "0" ]; then
if [ "$HISTCONTROL" = "ignorespace" ] ; then
if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
if [ -r "$i" ]; then
if [ "${-#*i}" != "$-" ]; then
[root@rhcsa1 ~]#
[root@rhcsa1 ~]# touch /var/tmp/pattern
[root@rhcsa1 ~]# grep then /etc/profile > /var/tmp/pattern
[root@rhcsa1 ~]# cat /var/tmp/pattern
if [ "$2" = "after" ] ; then
if [ -x /usr/bin/id ]; then
if [ -z "$EUID" ]; then
if [ "$EUID" = "0" ]; then
if [ "$HISTCONTROL" = "ignorespace" ] ; then
if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
if [ -r "$i" ]; then
if [ "${-#*i}" != "$-" ]; then

Thanks!
 
Old 01-14-2017, 03:14 AM   #7
grail
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Thanks for the reply and effort

Here are a few pointers:

1. Please use [code][/code] tags when showing code or data that requires formatting be kept or to make something more readable

2. You should refrain from using the root account to practice. Whilst your current testing does not affect an important file like /etc/profile, future testing may not be so kind and the root account is unforgiving and in many instances will not ask if you are sure you want to make the changes you might do!!

3. Have you looked at the grep man page? If you did you find there are a great number of switches which grep understands and will assist in your future testing. To launch the page simply type:
Code:
man grep

Let us know how you get on?
 
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