13 Must‑Have Linux Ops Tools and Quick Installation Guides

1. Nethogs – Process Bandwidth Monitor

Nethogs is a terminal‑based network traffic monitor that shows bandwidth usage per process.

# yum -y install libpcap-devel ncurses-devel
# tar zxvf nethogs-0.8.0.tar.gz
# cd nethogs
# make && make install
# nethogs eth0

2. IOZone – Disk I/O Performance Test

IOZone evaluates file system read/write performance across different operating systems.

# tar xvf iozone3_420.tar
# cd iozone3_420/src/current
# make linux
# ./iozone -a -n 512m -g 16g -i 0 -i 1 -i 5 -f /mnt/iozone -Rb ./iozone.xls

-a : enable automatic mode

-n : minimum file size (KB) for auto mode

-g : maximum file size (KB) for auto mode

-i : specify which test to run

-f : output file name (deleted after completion)

-R : generate Excel output to stdout

-b : write output to a specified file

3. IOTop – Real‑Time Disk I/O Monitor

IOTop displays real‑time disk I/O usage, similar in style to the top command.

# yum -y install iotop

4. IPtraf – Simple Network Traffic Analyzer

IPtraf provides a straightforward view of network traffic statistics on Linux.

# yum -y install iptraf

5. IFTop – Real‑Time Network Bandwidth Monitor

IFTop is a top‑like tool for monitoring network traffic, offering a more visual interface than iptraf.

# tar zxvf iftop-0.17.tar.gz
# cd iftop-0.17
# ./configure
# make && make install
# iftop -i eth0

TX – transmitted traffic

RX – received traffic

TOTAL – total traffic

Cumm – cumulative traffic since start

peak – traffic peak

rates – average traffic over 2 s, 10 s, 40 s intervals

6. HTop – Interactive Process Viewer

HTop is an interactive process browser that can replace the default top command.

# yum -y install htop

7. NMON – System Performance Monitor

NMON is a widely used monitoring and analysis tool for AIX and various Linux distributions.

# chmod +x nmon_x86_64_rhel6
# mv nmon_x86_64_rhel6 /usr/sbin/nmon
# nmon

8. MultiTail – Simultaneous Log Monitoring

MultiTail opens multiple windows in a console to monitor several log files at once, similar to the tail command.

# yum -y install multitail
# multitail -e "fail" /var/log/secure   # filter by keyword
# multitail -l "ping baidu.com"        # monitor command output
# multitail -i /var/log/messages -i /var/log/secure

9. Fail2ban – SSH Brute‑Force Protection

Fail2ban watches system logs, matches error patterns, and automatically adds firewall rules to block offending IPs.

# cd fail2ban-0.8.11
# python setup.py install
# cd files/
# cp ./redhat-initd /etc/init.d/fail2ban
# service fail2ban start
# chkconfig --add fail2ban
# chkconfig fail2ban on
# grep -v "^#" /etc/fail2ban/jail.conf | grep -v "^$"
# (example configuration snippets)
#   ignoreip = 127.0.0.1/8
#   bantime = 600
#   findtime = 600
#   maxretry = 3
#   backend = auto
#   [ssh-iptables]
#   enabled = true
#   filter = sshd
#   action = iptables[name=SSH, port=ssh, protocol=tcp]
#   logpath = /var/log/secure
#   maxretry = 5

Note: Fail2ban relies on iptables; if iptables is restarted, fail2ban must be restarted as well.

10. Tmux – Terminal Multiplexer

Tmux allows multiple terminal sessions to be managed within a single SSH connection, preventing disconnections from interrupting running tasks.

# yum -y install tmux

11. Agedu – Disk Space Usage Viewer

Agedu visualizes disk space consumption in a graphical manner.

# tar zxvf agedu-0.r9723.tar.gz
# cd agedu-0.r9723
# ./configure
# make && make install
# agedu -s /            # scan filesystem
# agedu -w --address 192.168.0.10:80   # view via web interface

12. NMap – Network Scanner

NMap is a powerful network discovery and security auditing tool.

# tar jxvf nmap-6.40.tar.bz2
# cd nmap-6.40
# ./configure
# make && make install
# nmap 192.168.0.10                # basic host scan
# nmap -O 192.168.0.10             # OS detection
# nmap -A 192.168.0.10             # comprehensive scan
# nmap 192.168.0.0/24              # scan an entire subnet

-sS TCP SYN scan

-sV service/version detection

13. Httperf – Web Stress Testing

Httperf extends the functionality of ApacheBench, allowing detailed performance and stability testing of web services.

# tar zxvf httperf-0.9.0.tar.gz
# cd httperf-0.9.0
# ./configure
# make && make install
# httperf --hog --server=192.168.0.202 \
    --uri=/index.html --num-conns=10000 \
    --wsess=10,10,0.1

Parameters:

--hog : generate as many connections as possible

--num-conns : total number of connections (e.g., 10000)

--wsess : simulate user sessions (sessions, requests per session, think time)

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