Unix - Bits and Pieces Part 1

In this blog post series, I'll be updating the post with random unix commands that might be of use to DBAs at regular intervals.

1. Trim Alert log contents

It becomes tedious job when we have to deal with a huge alert log and it gets worse if we have to dig a month old or a week old alert log contents for troubleshooting. So the below command can be used to trim the contents of alert log for a particular period of time.

# This is the format used
sed -n '/From date pattern / , /To date pattern/p' < input_file > output_file
# This is an example
sed -n '/Jul 23 / , /Jul 26/p' < alter_ORACLESID.log > 4days_trimmed.txt

2. Details of CPU available

The details of memory information is available below
Memory Information of different OS platforms
The Details of CPU available can be found by using the commands below in Linux servers.

# -- gives number of CPU
nproc
# Details of CPU from /proc/cpuinfo in human readable format
lscpu
# Details from cpuinfo directly
cat /proc/cpuinfo

For HP-UX the below commands can be used

# For details of procs
ioscan -fnk|grep proc 
# For number of  procs
ioscan -k|grep processor|wc -l
# For details of overall system 
top

For AIX use any of the below.

prtconf -s
pmcycles -m
lsdev -Cc processor
bindprocessor -q

3. Create multiple directories under all directories

If we are required to create multiple directories inside all the available directories the below command can be used
For eg., lets take a directory where envmt has 4 directories dir1, dir2, dir3, dir4
Now we need to create control,bad,param,log directories under each of all the directories under envmt. Illustration is as follows

$ cd envmt
$ ls -lrt
total 16
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:07 dir4
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:07 dir3
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:07 dir2
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:07 dir1
$ ls -l dir1
total 0
$ ls -l dir2
total 0
$ for dir in */; do mkdir -- "$dir"/{control,bad,param,log}; done
$ ls -l dir1
total 16
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 bad
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 control
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 log
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 param
$ ls -l dir2
total 16
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 bad
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 control
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 log
drwxr-xr-x 2 oracle dba 4096 Jul 27 17:08 param

Now control,bad,param,log directories are created in dir1, dir2, dir3, dir4 directories. This saves a lot of time while doing any job.

4. Search and replace in all files

The following command can be used to search and replace a word in all the files inside a directory. This is useful when we have configuration files stored where all the files should be updated with same username or servername, etc. 

# This is the format used
grep -rl 'search_string' ./ | xargs sed -i 's/search_string/replace_with_string/g'
# This is an example
grep -rl 'STDBCS01' ./ | xargs sed -i 's/STDBCS01/DVDBCS01/g'

If this find and replace is required for a single file, then it can be done by opening the file in vi editor

# open file
vi file_name
# Use below command to find and replace 
# g denotes global. Remove g if find and replace is required only for the particular line
:%s/search_string/replace_with_string/g
# save file and exit
:wq

5. Email attachment from servers

Email attachments can be sent with uuencode and the command is as below.
Tested in AIX and Linux

uuencode file1 file1 |mailx -s "Subject" nagulan.selvakumar@my.company.com

The below command is used to send multiple attachments in a single email

uuencode r1.tar.gz r1.tar.gz > /tmp/out.mail
uuencode r2.tar.gz r2.tar.gz >> /tmp/out.mail
uuencode r3.tar.gz r3.tar.gz >> /tmp/out.mail
echo "msg body"  >> /tmp/out.mail
mail -s "Reports" nagulan.selvakumar@my.company.com < /tmp/out.mail

We do have another package "mutt" to send emails which can be utilized as below.
Tested in Linux

echo "This is the message body" | mutt -a file_to_attach -s "subject of message" nagulan.selvakumar@my.company.com 

Happy working!