Discover DevOps roles and learn Linux from basics to advanced at DevOpsRoles.com. Detailed guides and in-depth articles to master Linux for DevOps careers.
diff command means Compare files line by line.
diff [OPTION]… FILES
On the man page, the describes it
$ diff huuphan.txt devopsroles.txtdiff command is a simple command in Linux. It is the most popular in use terminal Linux compare files line by line. Thank you for reading the DevopsRoles page!
kill command means Terminate a process (kill PID_of_target_process).
kill [-signal|-s signal|-p] [-q value] [-a] [–] pid|name…
kill -l [number] | -L
On the man page the describes it
# kill -9 1234To display all the available signalsadd new files to the existing zip file
[vagrant@DevopsRoles ~]$ kill -l 1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM 16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP 21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ 26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO 30) SIGPWR 31) SIGSYS 34) SIGRTMIN 35) SIGRTMIN+1 36) SIGRTMIN+2 37) SIGRTMIN+3 38) SIGRTMIN+4 39) SIGRTMIN+5 40) SIGRTMIN+6 41) SIGRTMIN+7 42) SIGRTMIN+8 43) SIGRTMIN+9 44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12 47) SIGRTMIN+13 48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14 51) SIGRTMAX-13 52) SIGRTMAX-12 53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9 56) SIGRTMAX-8 57) SIGRTMAX-7 58) SIGRTMAX-6 59) SIGRTMAX-5 60) SIGRTMAX-4 61) SIGRTMAX-3 62) SIGRTMAX-2 63) SIGRTMAX-1 64) SIGRTMAX
kill command in Linux is a simple command in Linux. It is the most popular in use terminal Linux terminate a process. Thank you for reading the DevopsRoles page!
ps command in Linux means ps displays information about a selection of the active processes. In the Linux operating system, managing and monitoring processes is a crucial task for system administrators and users alike. The ps command is an essential tool for viewing the currently running processes on a system.
It provides detailed information about each process, including its process ID (PID), the user who owns the process, and the resources it is consuming. In this article, we will explore the ps command in detail, learn how to use it effectively and provide practical examples to demonstrate its capabilities in real-world scenarios.
ps [options]
According to the man page, the ps the command provides a snapshot of the current processes.
For more detailed information about the ps command, you can use:
man ps$ psDisplay User Running Processes
[vagrant@DevopsRoles ~]$ ps -X #To display a user’s processes by real user ID (RUID) [vagrant@DevopsRoles ~]$ ps -fU vagrant
Display Group Processes
[vagrant@DevopsRoles ~]$ ps -fG vagrant
print a process tree for a given process
[vagrant@DevopsRoles ~]$ ps -ef --forest | grep -v grep | grep sshd root 2414 1 0 06:38 ? 00:00:00 /usr/sbin/sshd -D -u0 root 4087 2414 0 06:39 ? 00:00:00 _ sshd: vagrant [priv] vagrant 4090 4087 0 06:39 ? 00:00:00 _ sshd: vagrant@pts/0
Print Process Threads
[vagrant@DevopsRoles ~]$ ps -fL -C sshd UID PID PPID LWP C NLWP STIME TTY TIME CMD root 2414 1 2414 0 1 06:38 ? 00:00:00 /usr/sbin/sshd -D -u0 root 4087 2414 4087 0 1 06:39 ? 00:00:00 sshd: vagrant [priv] vagrant 4090 4087 4090 0 1 06:39 ? 00:00:00 sshd: vagrant@pts/0 root 4730 2414 4730 3 1 07:17 ? 00:00:00 sshd: vagrant [priv] vagrant 4733 4730 4733 0 1 07:17 ? 00:00:00 sshd: vagrant@pts/1
To view the PID, PPID, user name, and command of a process.
[vagrant@DevopsRoles ~]$ ps -eo pid,ppid,user,cmd | grep vagrant 4087 2414 root sshd: vagrant [priv] 4090 4087 vagrant sshd: vagrant@pts/0 4091 4090 vagrant -bash 4730 2414 root sshd: vagrant [priv] 4733 4730 vagrant sshd: vagrant@pts/1 4734 4733 vagrant -bash 4770 4091 vagrant ps -eo pid,ppid,user,cmd 4771 4091 vagrant grep --color=auto vagrant
Find the top running processes by highest memory and CPU usage in Linux.
[vagrant@DevopsRoles ~]$ ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head
PID PPID CMD %MEM %CPU
2413 1 /usr/bin/python2 -Es /usr/s 3.4 0.0
1666 1 /usr/sbin/NetworkManager -- 1.7 0.0
1502 1 /usr/lib/polkit-1/polkitd - 1.6 0.0
1 0 /usr/lib/systemd/systemd -- 1.2 0.0
4730 2414 sshd: vagrant [priv] 1.1 0.0
4087 2414 sshd: vagrant [priv] 1.1 0.0
2359 1666 /sbin/dhclient -d -q -sf /u 1.0 0.0
1076 1 /usr/lib/systemd/systemd-ud 0.9 0.0
2418 1 /usr/sbin/rsyslogd -n 0.9 0.0
[vagrant@DevopsRoles ~]$ ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head
PID PPID CMD %MEM %CPU
1 0 /usr/lib/systemd/systemd -- 1.2 0.0
2 0 [kthreadd] 0.0 0.0
3 2 [ksoftirqd/0] 0.0 0.0
5 2 [kworker/0:0H] 0.0 0.0
6 2 [kworker/u2:0] 0.0 0.0
7 2 [migration/0] 0.0 0.0
8 2 [rcu_bh] 0.0 0.0
9 2 [rcu_sched] 0.0 0.0
10 2 [lru-add-drain] 0.0 0.0
ps command in Linux is a simple command in Linux. The ps command is a powerful and versatile tool in Linux for monitoring and managing system processes. By mastering its options and syntax, you can gain valuable insights into the processes running on your system, diagnose issues, and optimize performance.
Hopefully, this article has provided you with a clearer understanding of how to use the ps command effectively and apply it in your daily tasks. Keep exploring and leveraging the powerful commands in Linux to enhance your efficiency and productivity in system administration and process management. Thank you for reading the DevopsRoles page!
top command means Display Linux processes.
top -hv|-bcEHiOSs1 -d secs -n max -u|U user -p pid -o fld -w [cols]
In man page the describe it
$ toptop command is the simple command in Linux. It is the most popular in use terminal Linux display Linux processes. Thank you for reading the DevopsRoles page!
grep command in Linux means grep prints the matching lines. In the Linux operating system, searching for specific text patterns within files is a common task that is essential for system administrators, developers, and users alike.
The grep command is a powerful and versatile tool used for searching and filtering text based on patterns. It supports regular expressions, allowing users to perform complex searches with ease. In this article, we will explore the grep command in detail, learn how to use it effectively, and provide practical examples that demonstrate its capabilities in real-world scenarios.
grep [OPTION…] PATTERNS [FILE…]
grep [OPTION…] -e PATTERNS … [FILE…]
grep [OPTION…] -f PATTERN_FILE … [FILE…]
According to the man page, the grep command in Linux prints lines that match a given pattern.
For more detailed information about the grep command, you can use:
man grep$ grep 'devopsroles' /home/huupv/devopsroles.txt// Search firmware in any case root@DevopsRoles ~]# grep -i -w 'firmware' anaconda-ks.cfg -aic94xx-firmware -alsa-firmware -alsa-tools-firmware -ivtv-firmware -iwl100-firmware -iwl1000-firmware -iwl105-firmware -iwl135-firmware -iwl2000-firmware -iwl2030-firmware -iwl3160-firmware -iwl3945-firmware -iwl4965-firmware -iwl5000-firmware -iwl5150-firmware -iwl6000-firmware -iwl6000g2a-firmware -iwl6000g2b-firmware -iwl6050-firmware -iwl7260-firmware -iwl7265-firmware -linux-firmware //Search match word Linux or UNIX in any case [root@DevopsRoles ~]# grep -i -w '^firmware' anaconda-ks.cfg // Search Alphanumeric Characters [root@DevopsRoles ~]# grep "^[[:alnum:]]" anaconda-ks.cfg // Search Alpha Characters [root@DevopsRoles ~]# grep "^[[:alpha:]]" anaconda-ks.cfg // Search Blank Characters [root@DevopsRoles ~]# grep "^[[:blank:]]" anaconda-ks.cfg // Search Digit Characters [root@DevopsRoles ~]# grep "^[[:digit:]]" anaconda-ks.cfg // Search Lower Letters [root@DevopsRoles ~]# grep "^[[:lower:]]" anaconda-ks.cfg // Search Punctuation Characters [root@DevopsRoles ~]# grep "^[[:punct:]]" anaconda-ks.cfg // Search Uppercase Letters [root@DevopsRoles ~]# grep "^[[:upper:]]" anaconda-ks.cfg
How to match an only dot (.)
[root@DevopsRoles ~]# grep 'conf\.d' anaconda-ks.cfg pushd /etc/dracut.conf.d /etc/dracut.conf.d/vmware-fusion-drivers.conf /etc/dracut.conf.d/hyperv-drivers.conf /etc/dracut.conf.d/nofloppy.conf
Read all files under each directory, recursively
[root@DevopsRoles ~]# grep -R "firmware" /root /root/original-ks.cfg:-aic94xx-firmware /root/original-ks.cfg:-alsa-firmware /root/original-ks.cfg:-alsa-tools-firmware /root/original-ks.cfg:-ivtv-firmware /root/original-ks.cfg:-iwl100-firmware /root/original-ks.cfg:-iwl1000-firmware /root/original-ks.cfg:-iwl105-firmware /root/original-ks.cfg:-iwl135-firmware /root/original-ks.cfg:-iwl2000-firmware /root/original-ks.cfg:-iwl2030-firmware /root/original-ks.cfg:-iwl3160-firmware /root/original-ks.cfg:-iwl3945-firmware /root/original-ks.cfg:-iwl4965-firmware /root/original-ks.cfg:-iwl5000-firmware /root/original-ks.cfg:-iwl5150-firmware /root/original-ks.cfg:-iwl6000-firmware /root/original-ks.cfg:-iwl6000g2a-firmware /root/original-ks.cfg:-iwl6000g2b-firmware /root/original-ks.cfg:-iwl6050-firmware /root/original-ks.cfg:-iwl7260-firmware /root/original-ks.cfg:-iwl7265-firmware /root/original-ks.cfg:-linux-firmware /root/anaconda-ks.cfg:-aic94xx-firmware /root/anaconda-ks.cfg:-alsa-firmware /root/anaconda-ks.cfg:-alsa-tools-firmware /root/anaconda-ks.cfg:-ivtv-firmware /root/anaconda-ks.cfg:-iwl100-firmware /root/anaconda-ks.cfg:-iwl1000-firmware /root/anaconda-ks.cfg:-iwl105-firmware /root/anaconda-ks.cfg:-iwl135-firmware /root/anaconda-ks.cfg:-iwl2000-firmware /root/anaconda-ks.cfg:-iwl2030-firmware /root/anaconda-ks.cfg:-iwl3160-firmware /root/anaconda-ks.cfg:-iwl3945-firmware /root/anaconda-ks.cfg:-iwl4965-firmware /root/anaconda-ks.cfg:-iwl5000-firmware /root/anaconda-ks.cfg:-iwl5150-firmware /root/anaconda-ks.cfg:-iwl6000-firmware /root/anaconda-ks.cfg:-iwl6000g2a-firmware /root/anaconda-ks.cfg:-iwl6000g2b-firmware /root/anaconda-ks.cfg:-iwl6050-firmware /root/anaconda-ks.cfg:-iwl7260-firmware /root/anaconda-ks.cfg:-iwl7265-firmware /root/anaconda-ks.cfg:-linux-firmware
To perform a case-insensitive search, use the -i option:
grep -i "search_string" filenameTo search for a pattern in all files within a directory recursively, use the -r option:
grep -r "search_string" /path/to/directoryTo display the line numbers of the matching lines, use the -n option:
grep -n "search_string" filenameTo display lines that do not match the pattern, use the -v option:
grep -v "search_string" filenameTo count the number of matching lines, use the -c option:
grep -c "search_string" filenameTo use regular expressions for more complex searches, use the -E option (for extended regular expressions):
grep -E "pattern" filenamegrep stands for “Global Regular Expression Print,” highlighting its ability to search globally for patterns using regular expressions.
grep search binary files?Yes, but by default, it skips binary files. Use the -a option to treat binary files as text:
grep -a "pattern" binaryfile
Use the -q option for quiet mode:
grep -q "pattern" file.txt && echo "Match found"
grep to search for multiple patterns simultaneously?Yes, with the -e option:
grep -e "pattern1" -e "pattern2" file.txt
grep handle large files?grep is optimized for performance, but for extremely large files, consider using it with tools like xargs or limiting output with head or tail.
grep command in Linux is a simple command in Linux. The grep command is an indispensable tool in Linux for searching and filtering text. By mastering its options and syntax, you can efficiently locate and manipulate data within files, enhancing your productivity in system administration and development tasks.
Hopefully, this article has provided you with a clearer understanding of how to use the grep command examples effectively and apply it in your daily activities. Keep exploring and leveraging the powerful commands in Linux to improve your efficiency and proficiency in managing and processing text data. Thank you for reading the DevopsRoles page!
The find command in Linux is one of the most powerful tools for system administrators and developers. It allows users to search for files and directories based on a variety of criteria such as name, type, size, permissions, and modification time. Whether you’re troubleshooting, managing files, or automating tasks, mastering the find command can significantly boost your productivity.
In this article, we’ll explore the ins and outs of the find command, starting with the basics and moving to advanced use cases. By the end, you’ll have a strong grasp of how to wield this versatile tool effectively.
find CommandThe general syntax of the find command is as follows:
find [-H] [-L] [-P] [-D debugopts] [-Olevel] [starting-point…] [expression]
On the man page, the describes it.
$ find /home/huupv -name devopsroles.txt// Full command
[vagrant@DevopsRoles ~]$ find /home/vagrant/ -name huupv.csv -type f -print
/home/vagrant/DevopsRoles/Devops/huupv.csv
// Search DevopsRoles directory
[vagrant@DevopsRoles ~]$ find /home/vagrant/ -name DevopsRoles -type d
/home/vagrant/DevopsRoles
/home/vagrant/DevopsRoles/Devops/DevopsRoles
// Search Multiple Directory
[vagrant@DevopsRoles ~]$ sudo find /opt /tmp /home/vagrant -name huupv.csv -type f
/home/vagrant/DevopsRoles/Devops/huupv.csv
//find all files not ending in ".csv"
[vagrant@DevopsRoles ~]$ find /home/vagrant -type f -not -name "*.csv"
/home/vagrant/.bash_logout
/home/vagrant/.bash_profile
/home/vagrant/.bashrc
/home/vagrant/.ssh/authorized_keys
/home/vagrant/DevopsRoles/Devops/xxx
/home/vagrant/Devops.zip
/home/vagrant/.bash_history
//change csv files to mode 644
[vagrant@DevopsRoles ~]$ find /home/vagrant -name "*.csv" -type f -exec chmod 644 {} \;
//run ls command on files found with find command
[vagrant@DevopsRoles ~]$ find /home/vagrant -name "*.csv" -type f -exec ls -ld {} \;
-rw-r--r--. 1 vagrant vagrant 0 Oct 1 06:45 /home/vagrant/DevopsRoles/Devops/huupv.csv
//How to find and copy file .csv to folder /tmp/
[vagrant@DevopsRoles ~]$ find /home/vagrant -type f -name "*.csv" -exec cp {} /tmp/ \;
How to find and delete
vagrant@DevopsRoles ~]$ find /home/vagrant/ -type f -name "huupv*" -exec rm {} \;Find files by modification time
[vagrant@DevopsRoles ~]$ find /home/vagrant/ -mtime 1 # 24 hours
[vagrant@DevopsRoles ~]$ find /home/vagrant/ -mtime -7 # last 7 daystar command with the find command
[vagrant@DevopsRoles ~]$ find /home/vagrant -type f -name "*.java" | xargs tar zcvf ./myfile.tar tar: Removing leading `/' from member names /home/vagrant/DevopsRoles/Devops/a.java /home/vagrant/DevopsRoles/Devops/b.java /home/vagrant/home/vagrant/DevopsRoles/Devops/a.java /home/vagrant/home/vagrant/DevopsRoles/Devops/b.java [vagrant@DevopsRoles ~]$ ll total 8 drwxrwxr-x. 3 vagrant vagrant 20 Oct 1 06:51 DevopsRoles -rw-rw-r--. 1 vagrant vagrant 788 Oct 1 07:00 Devops.zip drwxrwxr-x. 3 vagrant vagrant 21 Nov 11 15:22 home -rw-rw-r--. 1 vagrant vagrant 178 Nov 11 15:23 myfile.tar [vagrant@DevopsRoles ~]$ tar -xvf myfile.tar home/vagrant/DevopsRoles/Devops/a.java home/vagrant/DevopsRoles/Devops/b.java home/vagrant/home/vagrant/DevopsRoles/Devops/a.java home/vagrant/home/vagrant/DevopsRoles/Devops/b.java
The find command in Linux is an indispensable tool for locating files and directories based on a variety of criteria. From simple name searches to advanced permission-based queries, find offers unmatched flexibility. Whether you’re a system administrator or a casual user, mastering this command can streamline your workflow and improve efficiency.
Start experimenting with the examples provided in this guide to become proficient in using the find command. For more details, refer to the official Linux documentation linked above. Thank you for reading the DevopsRoles page!
sort command in Linux is a powerful utility that organizes text lines in a file or input stream. Whether you’re managing log files, organizing data, or processing large datasets, sort offers robust sorting capabilities, from simple alphabetical order to complex numerical arrangements. This guide delves into the sort command, showcasing its versatility with practical examples and tips for advanced usage.
The sort command in Linux arranges lines of text in a specified order. It supports multiple options for sorting, including numerical, alphabetical, case-insensitive, and more.
sort [OPTION]… [FILE]…
On the man page, the describes it
$ sort devopsroles.txtsort Command-n: Numerical sort.-r: Reverse order.-k: Sort by a specific column.-t: Specify a delimiter for field separation.-u: Remove duplicate lines.The sort command allows combining multiple options to achieve complex sorting tasks.
sort file.txt
This sorts the lines in file.txt alphabetically.
banana
apple
cherry
apple
banana
cherry
sort -n numbers.txt
Sorts the file numerically.
10
2
30
2
10
30
sort -r file.txt
Sorts the lines in reverse alphabetical order.
sort -k 2 data.txt
Sorts the file based on the second column.
John 25
Alice 30
Bob 22
Bob 22
John 25
Alice 30
sort -t: -k 2 scores.txt
Sorts the file by the second field, with : as the delimiter.
Alice:85
Bob:90
John:78
John:78
Alice:85
Bob:90
sort -u file.txt
Removes duplicate lines during sorting.
For large files, use the -T option to specify a directory for temporary storage:
sort -T /tmp largefile.txt
sort -f file.txt
Sorts lines without considering case sensitivity.
sort -m file1.txt file2.txt
Combines two pre-sorted files into one sorted output.
sort -M months.txt
Sorts lines based on month names (e.g., Jan, Feb).
Combine sort with uniq for advanced deduplication:
sort file.txt | uniq
Use the -r option:
sort -r file.txt
sort handle case-insensitive sorting?Yes, the -f flag enables case-insensitive sorting.
Use the -T option to specify a temporary directory with sufficient space.
-k option do in sort?The -k option sorts based on a specified column or field.
Use the -n option:
sort -n file.txt
sort command is a simple command in Linux. It is the most popular in use terminal Linux sort lines of text files. Thank you for reading the DevopsRoles page!
The echo command in Linux is a versatile tool used for printing text or variables to the terminal or redirecting them to a file. It is a simple yet powerful command that finds wide usage in shell scripting and day-to-day Linux operations.
In this tutorial, we will delve into the echo command, exploring its functionality and providing practical examples to illustrate its usage. echo command means Echo the STRING(s) to standard output.
echo [SHORT-OPTION]… [STRING]…
echo LONG-OPTION
On the man page, the describes it
$ echo "Welcome to DevopsRoles.com !"echo "Hello, world!"name="HuuPV"
age=33
echo "Name: $name"
echo "Age: $age"echo -n "This is "
echo "a single line."echo -e "Line 1\nLine 2\tTabbed Line 3"echo "This is some content." > output.txtThis command creates a file named output.txt and writes the text “This is some content.” into it.
echo command in Linux is a simple command in Linux. It is the most popular in-use terminal Linux displays a line of text. Thank you for reading the DevopsRoles page!
less command means less is a filter for paging which allows backward movement in the file as well as forward. movement.
less [options]
On the man page, the describes it
$ less /proc/cpuinfo
$ less /home/huupv/devopsroles.txtss command is the simple command in Linux. It is the most popular in use terminal Linux opposite of more. less command doesn’t support syntax highlighting. Thank you for reading the DevopsRoles page!
head command means Print the first 10 lines of each FILE to standard output.
head [OPTION]… [FILE]…
On the man page, the describes it
$ head devopsroles.csvhead is a simple command in Linux. It is the most popular in use terminal Linux output the first part of files. Thank you for reading the DevopsRoles page!