/usr/sbin/prtconf | grep Mem  	-- For Solaris
dmesg 					-- For HP-UX
lsdev -C | grep mem  			-- For AIX
lsattr -El mem0 ( output from previous command) -- For AIX
free 					-- For Linux
uerf -r 300 | grep -I mem		-- DEC-UNIX

find / -print | grep -i z.sql  -- In root mount point searching for file "z.sql"
find /usr/lib -name "*raj*" /*finding can’t remember the exact name of*/
find . -size +20000 /*find files bigger than 20000 blocks, about 10MB )*/
find . -size +20000 -mtime -1 -ls
find . -mtime -1 /*Find files or directories modified in last day*/
find /tmp -atime +45 /*find files not accessed (read) in 45 days*/
find . -name "*.c" |xargs grep -l libsocket /*look for a particular word in all your .c files*/

sar -u 1 10   /*if I run sar 1 10 it will report to the screen, 10 instances every one second*/

vmstat 1 5 /*vmstat [interval] [count]*/

iostat -x 1 5  /*iostat [interval] [count]*/

/usr/sbin/swap -s /*solaris*/

uptime /*check system load average: an uptime more than double the number of CPUs is getting a bit busy*/

/usr/ucb/ps uax |head /*solaris*/

/usr/ucb/ps vax |head /*solaris*/

df -h or df -k or df -g /*shows all mounted filesystems*/
df -h /u01 /*show space for specified mountpoing /u01 */
du -sh /home/oracle /*To find size of a directory */
du -sk
[root@rac1 ~]# du -k /u01 | sort -r -n -k 1 | head -20 | awk ' { print $2 "....."$1/1024 "MB" } '
/u01.....48585.8MB
/u01/app.....40167.6MB
/u01/app/oracle.....21521.9MB
/u01/app/oracle/product.....20262.3MB
/u01/app/grid/product/12.2.....17900.2MB
/u01/app/grid/product.....17900.2MB
/u01/app/grid.....17900.2MB
/u01/app/oracle/product/12.2.0/dbhome_1.....13300.9MB
/u01/app/oracle/product/12.2.0.....13300.9MB
/u01/app/oracle/product/12.2/db_1.....6961.39MB
/u01/app/oracle/product/12.2.....6961.39MB
/u01/stage/30920127.....5662.84MB
/u01/stage.....5662.84MB
/u01/app/oracle/product/12.2.0/dbhome_1/dbs.....3836.5MB
/u01/app/oracle/product/12.2/db_1/database.....3667.68MB
/u01/app/oracle/product/12.2/db_1/database/stage.....3665.52MB
/u01/app/grid/product/12.2/.patch_storage.....3249.18MB
/u01/stage/30920127/30869447.....3093.78MB
/u01/stage/30920127/30869447/files.....3093.64MB
/u01/app/oracle/product/12.2/db_1/database/stage/Components.....3053.15MB
[root@rac1 ~]#

# top /*it will show information like tasks, memory, cpu and swap. Press ‘q‘ to quit window*/
# top -u oracle /*will display specific User process details*/
# top ---> then press z /*will display running process in color which may help you to identified running process easily*/
# top ---> then press c /*will display absolute path of running process*/
# top ---> then press d /*Default screen refresh interval is 3.0 seconds, can change pressing ‘d‘ option*/
# top ---> then press k /*You can kill PID in running top command without exiting from top window*/
# top ---> then press Shift+P /*to sort processes as per CPU utilization*/
# top ---> then press r /*To change the priority of the process (Renice a Process)*/
# top ---> then press Shift+W /*To save top command results*/
# top ---> then press h /*Getting Top Command Help*/
# top ---> then press Shift+O then press "a" /*press ‘a‘ letter to sort process with PID (Process ID)/*

psrinfo | wc -l /*Solaris --suppose virtual CPU*/
cat /proc/cpuinfo|grep processor|wc –l /*Linux*/
psrinfo -v|grep "Status of processor"|wc –l /*Solaris*/
lsdev -C|grep Process|wc –l /*AIX*/
ioscan -C processor | grep processor | wc -l /*HP-UX*/

truss -p  /*Solaris and AIX*/
strace -p  /*Linux*/
trace -p  /*Tru 64*/

Linux: /var/log/messages
Solaris, HP Tru64: /var/adm/messages
HP-UX: /var/adm/syslog/syslog.log
AIX: /bin/errpt

uuencode 1.txt 2.txt | mailx -s "subject of mail" br8dba@gmail.com
OR
echo Body of the mail |mailx -s Attachment -a file.txt br8dba@gmail.com

TAR

tar -cvf /u01/zzz.tar /home/zzz/ /*will create tar file for /home/zzz directory, it will keep original files as it is*/
c – Creates a new .tar archive file.
v – Verbosely show the .tar file progress.
f – File name type of the archive file.

UNTAR

tar -xvf /u01/zzz.tar -C /home/oracle /*Untar files in specified Directory*/

TAR Compress
Create tar.gz Archive File use option z
tar cvzf /u01/zzz.tar.gz /home/zzz /*will create tar file for /home/zzz directory*/

TAR UnCompress 
tar -xvf /u01/zzz.tar.gz -C /home/oracle /*Untar files in specified Directory*/


TAR Compress tar.bz2

Create tar.bz2 Archive File
The bz2 feature compress and create archive file less than the size of the gzip.
The bz2 compression takes more time to compress and decompress files as compared to gzip which takes less time. 
To create highly compressed tar file we use option as j.

tar cvfj /u01/zzz.tar.bz2 /home/zzz/ -- /*will create tar file for /home/zzz directory*/

TAR UnCompress tar.bz2
tar -xvf /u01/zzz.tar.bz2 -C /home/oracle /*Untar files in specified Directory*/

List Content of tar Archive File

tar -tvf /u01/zzz.tar
tar -tvf /u01/zzz.tar.gz
tar -tvf /u01/zzz.tar.bz2

Untar Single file from tar File

tar -xvf /u01/zzz.tar init.ora
tar -zxvf /u01/zzz.tar.gz init.ora
tar -jxvf /u01/zzz.tar.gz.bz2 init.ora
or
tar --extract --file=/u01/zzz.tar init.ora
tar --extract --file=/u01/zzz.tar.gz init.ora
tar --extract --file=/u01/zzz.tar.gz.bz2 init.ora

Untar Multiple files from tar, tar.gz and tar.bz2 File

tar -xvf /u01/zzz.tar "file 1" "file 2" 
tar -zxvf /u01/zzz.tar.gz "file 1" "file 2" 
tar -jxvf /u01/zzz.tar.bz2 "file 1" "file 2"


Extract Group of Files using Wildcard

tar -xvf /u01/zzz.tar --wildcards '*.php'
tar -zxvf /u01/zzz.tar.gz --wildcards '*.php'
tar -jxvf /u01/zzz.tar.bz2 --wildcards '*.php'

Zipping individual files
zip abc.zip file1 file2 file3

Zip a file or folder
zip archivename.zip file1 file2 folder1

Zip a folder (including all subdirectories)
zip -r folder1*

Zip a folder to a different location
zip -r /tmp/abc.zip /home/oracle/folder1

List all the files stored in a zip file
unzip -l abc.zip

Unzip
unzip abc.zip

To unzip to a specific directory use -d option
unzip abc.zip -d /tmp

Unzip specific file from an archive
unzip abc.zip test.sh

zipping a file with gzip command
gzip file1 file2 file3
oracle@rac1:~/test/test$ ls
dump.doc.gz  file1.gz  test.sh.gz <-- it will zip individually
oracle@rac1:~/test/test$
Note: Above gzip command will create files dump.doc.gz, file1.gz and test.sh.gz respectively by replacing original files.
To avoid deleting of original files, use -k(keep) option with zgip command

gzip  -k dump.doc file1 test.sh 
oracle@rac1:~/test/test$ ls
dump.doc  dump.doc.gz  file1  file1.gz  test.sh  test.sh.gz
oracle@rac1:~/test/test$

How to zip group of files to a gzip single compressed file
gzip don't know how to add files to a single comprss file and it just compress each file individually by default.

oracle@rac1:~/test/test$ cat dump.doc file1 test.sh | gzip > all.gz
oracle@rac1:~/test/test$ ls
all.gz  dump.doc  file1  test.sh
oracle@rac1:~/test/test$

Unzip the gzip file
gunzip all.gz

oracle@rac1:~/test/test$ ls
all.gz  dump.doc  file1  test.sh
oracle@rac1:~/test/test$ gunzip all.gz 
oracle@rac1:~/test/test$ ls
all  dump.doc  file1  test.sh <-- gzip file automatically deleted once unzipped