Linux Admin Tools

systeminfo

$ uname -mrs
$ lsb_release -a
$ dmesg | egrep -i 'err|warn|critical'
$ sudo tail -f /var/log/myapp

Linux System Hardware Information
--
sudo lshw -short
sudo lshw -html > lshw.html
# Hardware Info
dmidecode  -q | less
lshw
lshw -C disk
lscpu
lsusb -v
lspci
lspci -t
lspci -v

SCSI HW Info

lsblk
lsssci -s


Print Information about SATA Devices

sudo hdparm /dev/sda1
sudo hdparm -g /dev/sda1	


Extract Information about Hardware Components
sudo dmidecode -t memory
sudo dmidecode -t bios
sudo dmidecode -t processor
sudo dmidecode -t system

Vim editor	

0	move to beginning of the current line
$	move to end of line
n      search next  below
G - last line of file

To copy a directory from a local to remote system, use the -r option:

- scp -r /local/directory remote_username@10.10.0.2:/remote/directory
- scp -r  /home/thomasa/Documents/NSX  thomas@192.168.1.108:/data/NSX


Note taking - Connels
- scp -r /data/xwikiconfig_backups/ thomasa@192.168.1.12:/data/xwikiconfig_backups


cp

Copying files from one directory to other with all perm intact 

-a and -R is actually same ( recursive - ie: goes into directory)
-v shows versbose 

cp -aRv ash/ perm2

# Print Disk Usage Output In Human Readable Format with Grand Total
  du -ahc /Users/lnxadm
 
 # Print Disk Usage Output In Human Readable Format showing consumption
  du -h --max-depth=1 /var/log | sort -n -r 
  
 # Print Disk Usage with just Grand Total
 du -sh /Users/lnxadm
 
# Display Disk Usage Output In GB
  du -gsh /Users/lnxadm
  
# Check file system disk space usage with filesystem
  df -H .
  df -h --total

# Check Inode usage
  df -i

  

#To create a .tar archive file.
# tar -cvf <FileName.tar> <Files/Folders To Be Compressed>

#To create a .tar.gz archive file.
tar -zcvf <FileName.tar.gz> <Files/Folders To Be Compressed>

#To Decompress a .tar archive file.
# tar -xvf <FileName.tar>

To Decompress a .tar.gz archive file.
# tar -xzvf <FileName.tar.gz>

View the list of files in the ZIP archive without extracting it.
# zipinfo <FileName.zip>
# less <FileName.zip>

#create a zip file
zip filename.zip <filenames.txt>

#Unzip a file
unzip filename.zip

#link folder recursively into filename.zip
zip -r filename.zip somefiles

By default gzip removes the original file but if we wish to keep it we should use the '-c' option
# gzip -c myfile > filename.gz

# Compress multiple files into a single gzip
 gzip -c demo1.txt demo2.txt > filename.gz
 
# List the compressed file contents
gzip -l filename.gz

# View the actual contents of a gzip compressed file
zcat filename.gz

# Compress all files in a directory
gzip -r mydirectory

Decompress files with gzip
gzip -d  filename.gz
gunzip filename.gz

dd if=/dev/zero of=afile.txt  bs=1G  count=1

# To set a hostname, run
hostnamectl set-hostname <hostname>
# Check enteries in these files
vi /etc/sysconfig/network
$ vi /etc/hosts

[root@server1 ~]# nmcli con mod ens32 ipv4.address 192.168.1.10/24
[root@server1 ~]# nmcli con mod ens32 ipv4.gateway 192.168.1.

[root@server1 ~]# nmcli con mod ens32 ipv4.dns 192.168.1.1

MacBook-Air:demo root# dd if=/dev/zero of=afile.txt  bs=1G  count=1
1+0 records in
1+0 records out
1073741824 bytes transferred in 3.194800 secs (336090467 bytes/sec)
MacBook-Air:demo root# 
MacBook-Air:demo root# ls -alh
total 2097152
drwxr-xr-x   3 root  wheel    96B 27 Oct 10:29 .
drwxr-x---  13 root  wheel   416B 27 Oct 10:28 ..
-rw-r--r--   1 root  wheel   1.0G 27 Oct 10:29 afile.txt
MacBook-Air:demo root# 

-mtime +5:  Finds files that were modified 5 days ago.
-mtime -10: Finds all files that were modified in the last 10 days.
-mtime 10:  Find all files that were modified exactly 10 days ago.

# Finding the Top 5 Big Files
# find . -type f -exec ls -s {} \; | sort -n -r | head -5

The following command removes *.zip files that are over 100M.
# find / -type f -name *.zip -size +100M -exec rm -i {} \;"

Finds all the files (under root file system /) that got updated within the last day
 # find / -maxdepth 1 -newermt "2016-12-06"


# find . -type f -exec ls -s {} \; | sort -n -r | head -5

# find Files in a folder that were @Changed in last 15 days
  find . -type f -mtime -15 -ls

# find Files in a folder that were @Modified in last 15 days
  find . -type f -mtime 10 -ls

# find files that were modified within last 30 Mins
  find . -type d -mmin -30 -ls

# find only the folders modified in last 5 Days
  find . -type d -mtime -5 -ls

# List both Files and Folders that were modified in last 15 Days
  find . -mtime -15 -ls

# Find files that have been modified over a period of time
  find . -cmin -20 -ls

# Find list of files created today
  find . -type f -ctime -1 -ls

# find all files and folders modified in the Last 24 Hours
  find . -newermt "-24 hours" -ls  
 
# find modified files and folders starting from a given Date to the latest Date
   find . -newermt "2023-10-07" -ls
   

# Search files older than 20 days
find . -type f -mtime +20 -print

# Delete files older than 20 days

find. -type f -mtime +20 -exec rm -f {} \;
or
find . -type f -mtime +20 | xargs rm -f

# List files older than 10 days with tar.gz extension
find . -type f -name "*.tar.gz" -mtime +10 -print

# Delete it using one of the following commands.
find . -type f -name "*.tar.gz" -mtime +10 -exec rm -f {} \;
or
find . -type f -name ".tar.gz" -mtime +10 | xargs rm -f

# Command Syntax for removal
Just show files
find /var/log -type f -name '*.jpg' -mtime +30 -exec ls {} \;

# Remove files
find /var/log -type f -name '*.jpg' -mtime +30 -exec rm {} \;
Explanation
- First part is the path where your files are located.
- Second part -type is the file type f stands for files
- Thirdpart-name is for using the actual filenames
- Fourth part -mtime gets how many days the files older then will be listed. +30 is
for files older then 30 days.
- Fifth part -exec executes a command. In this case rm is the command, {} gets the
filelist and \; closes the command

# To copy a directory recursively to another location
cp -r /var/logs/ /home/vmadmin

# To copy a file with its permissions
cp -p /var/logs/demofile /home/vmadmin

# To prevent overwrite of a file if it exists in target
cp -n /var/logs/demofile /home/vmadmin

# Copying specific format of files
cp /var/logs/*.gz /home/vmadmin

# Copy hidden files 
cp -R /var/logs.* /home/vmadmin

watch tail -n 10 /var/log/vmware-network.1.log 

tail -f /var/log/vmware-network.1.log 

# Provides output from all areas 
journalctl -f

# 24 hour (Warnings, Errors and Critical) log summary
 grep -i "`date --date='yesterday' '+%b %e'`" /var/log/wifi.log | egrep -wi 'warning|error|critical' 

grep -v '^#' /etc/httpd/conf/httpd.conf | less