Commands using tail sorted by votes

Commands using tail (292)

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useful tail on /var/log to avoid old logs or/and gzipped files

with discard wilcards in bash you can "tail" newer logs files to see what happen, any error, info, warn... Show Sample Output

tail -f *[!.1][!.gz]

piscue · 2009-03-06 16:24:44 8

Follow the most recently updated log files

This command finds the 5 (-n5) most frequently updated logs in /var/log, and then does a multifile tail follow of those log files. Alternately, you can do this to follow a specific list of log files: sudo tail -n0 -f /var/log/{messages,secure,cron,cups/error_log} Show Sample Output
This is sample output - yours may be different.
```
==> /var/log/cron <==

==> /var/log/messages <==

==> /var/log/lastlog <==

==> /var/log/wtmp <==

==> /var/log/secure <==

==> /var/log/lastlog <==

==> /var/log/wtmp <==
&#65533;1pts/4ts/4myusermyhost.example.com&#65533;fJ&#65533;&#65533;?
==> /var/log/secure <==
Jul 21 18:36:19 thost sshd[12730]: Accepted password for myuser from 192.168.100.7 port 50066 ssh2
Jul 21 18:36:19 thost sshd[12730]: pam_unix(sshd:session): session opened for user myuser by (uid=0)
```
5

ls -drt /var/log/* | tail -n5 | xargs sudo tail -n0 -f

kanaka · 2009-07-22 14:44:41 22
When was your OS installed?

shows also time if its the same year or shows year if installed before actual year and also works if /etc is a link (mac os) Show Sample Output
This is sample output - yours may be different.
```
Jul 15 11:46
or
Dec 24 2006
```
5

ls -lct /etc/ | tail -1 | awk '{print $6, $7, $8}'

peshay · 2009-09-04 16:52:50 5

List your largest installed packages.

Calculates the size on disk for each package installed on the filesystem (or removed but not purged). This is missing the | sort -rn which would put the biggest packges on top. That was purposely left out as the command is slightly on the slow side Also you may need to run this as root as some files can only be checked by du if you can read them ;) Show Sample Output

This is sample output - yours may be different.

176     acl                                                                                                                                     
44      acpi                                                                                                                                    
396     acpi-support                                                                                                                            
32      acpi-support-base                                                                                                                       
108     acpid                                                                                                                                   
524     adduser                                                                                                                                 
408     akonadi-server                                                                                                                          
2416    akregator                                                                                                                               
388     alsa-base                                                                                                                               
1840    alsa-utils                                                                                                                              
1860    amor                                                                                                                                    
96      anacron                                                                                                                                 
120     apmd                                                                                                                                    
4512    apt                                                                                                                                     
104     apt-file                                                                                                                                
376     apt-utils                                                                                                                               
140     apt-xapian-index                                                                                                                        
9184    aptitude                                                                                                                                
112     at                                                                                                                                      
104     avahi-autoipd                                                                                                                           
252     avahi-daemon                                                                                                                            
260     base-files                                                                                                                              
100     base-passwd                                                                                                                             
du: cannot access `diverted by dash to: /usr/share/man/man1/sh.distrib.1.gz': No such file or directory                                         
du: cannot access `diverted by dash to: /bin/sh.distrib': No such file or directory

dpkg --get-selections | cut -f1 | while read pkg; do dpkg -L $pkg | xargs -I'{}' bash -c 'if [ ! -d "{}" ]; then echo "{}"; fi' | tr '\n' '\000' | du -c --files0-from - | tail -1 | sed "s/total/$pkg/"; done

pykler · 2009-10-12 14:57:54 5

tail: watch a filelog

-f file(s) to be monitorized -n number of last line to be printed on the screen in this example, the content of two files are displayed
This is sample output - yours may be different.
5

tail -n 50 -f /var/log/apache2/access_log /var/log/apache2/error_log

warlock · 2010-02-21 14:45:44 4
Top ten (or whatever) memory utilizing processes (with children aggregate)

This command loops over all of the processes in a system and creates an associative array in awk with the process name as the key and the sum of the RSS as the value. The associative array has the effect of summing a parent process and all of it's children. It then prints the top ten processes sorted by size. Show Sample Output
This is sample output - yours may be different.
```
2472    NetworkManager
3624    getty
3888    hald
3948    nm-system-setti
3968    gdm
4012    bash
6384    sshd
14348   apache2
20560   console-kit-dae
22104   mysqld
```
5

ps axo rss,comm,pid | awk '{ proc_list[$2]++; proc_list[$2 "," 1] += $1; } END { for (proc in proc_list) { printf("%d\t%s\n", proc_list[proc "," 1],proc); }}' | sort -n | tail -n 10

d34dh0r53 · 2010-03-03 16:41:05 5
Realtime lines per second in a log file

Using tail to follow and standard perl to count and print the lps when lines are written to the logfile.
This is sample output - yours may be different.
5

tail -f /var/log/logfile|perl -e 'while (<>) {$l++;if (time > $e) {$e=time;print "$l\n";$l=0}}'

madsen · 2011-06-21 10:28:26 7
Live filter a log file using grep and show x# of lines above and below
This is sample output - yours may be different.
4

tail -f <filename> | grep -C <# of lines to show above and below> <text>

manalang · 2009-02-06 17:19:01 11
How much RAM is Apache using?

Display the amount of memory used by all the httpd processes. Great in case you are being Slashdoted!
This is sample output - yours may be different.
4

ps -o rss -C httpd | tail -n +2 | (sed 's/^/x+=/'; echo x) | bc

ricardoarguello · 2009-07-31 15:15:08 9
get the latest version

to download latest version of "util", maybe insert a sort if they wont be shown in right order. curl lists all files on mirror, grep your util, tail -1 will gets the one lists on the bottom and get it with wget Show Sample Output
This is sample output - yours may be different.
```
for Sun Freeware
mirror=ftp://sunsite.informatik.rwth-aachen.de/pub/mirror/ftp.sunfreeware.com
pkg=perl
curl -l $mirror/intel/10/ 2>/dev/null | grep $pkg
perl-5.8.5-sol10-intel-local.gz
perl-5.8.7-sol10-x86-local.gz
perl-5.8.8-sol10-x86-local.gz

command above would download only perl-5.8.8-sol10-x86-local.gz
```
4

mirror=ftp://somemirror.com/with/alot/versions/but/no/latest/link; latest=$(curl -l $mirror/ 2>/dev/null | grep util | tail -1); wget $mirror/$latest

peshay · 2009-08-24 15:58:31 282
Analyse compressed Apache access logs for the most commonly requested pages
This is sample output - yours may be different.
4

zcat access_log.*.gz | awk '{print $7}' | sort | uniq -c | sort -n | tail -n 20

tkb · 2009-12-11 09:36:30 4
Quickly analyse an Apache error log

This searches the Apache error_log for each of the 5 most significant Apache error levels, if any are found the date is then cut from the output in order to sort then print the most common occurrence of each error. Show Sample Output
This is sample output - yours may be different.
```
  4  [emerg] (17)File exists: Couldn't create accept lock 
  20 [error] [client 1.2.3.4] File does not exist: /Welcome, referer: http://127.0.0.1/
  23 [warn] Init: Session Cache is not configured [hint: SSLSessionCache]
```
4

for i in emerg alert crit error warn ; do awk '$6 ~ /^\['$i'/ {print substr($0, index($0,$6)) }' error_log | sort | uniq -c | sort -n | tail -1; done

zlemini · 2010-04-15 21:47:18 3
Realtime apache hits per second

Change the cut range for hits per 10 sec, minute and so on... Grep can be used to filter on url or source IP. Show Sample Output
This is sample output - yours may be different.
```
     11 29/Apr/2010:13:03:01
     28 29/Apr/2010:13:03:02
      1 29/Apr/2010:13:03:01
      7 29/Apr/2010:13:03:02
      1 29/Apr/2010:13:03:00
      7 29/Apr/2010:13:03:02
     22 29/Apr/2010:13:03:03
```
4

tail -f access_log | cut -c2-21 | uniq -c

buzzy · 2010-04-29 11:16:54 6
Tail a log-file over the network

Netcat is used to serve a log-file over a network on port 1234. Point a browser to the specified server/port combo to view log-file updates in real-time.
This is sample output - yours may be different.
4

tail -f error_log | nc -l 1234

zlemini · 2010-05-07 18:14:04 8
Count number of hits per IP address in last 2000 lines of apache logs and print the IP and hits if hits > 20
This is sample output - yours may be different.
4

tail -n2000 /var/www/domains/*/*/logs/access_log | awk '{print $1}' | sort | uniq -c | sort -n | awk '{ if ($1 > 20)print $1,$2}'

allrightname · 2010-05-10 19:08:37 3
diff output of two commands

This only works in bash
This is sample output - yours may be different.
4

diff <(tail -10 file1) <(tail -10 file2)

elofland · 2010-05-20 14:04:17 5
Monitor a file with tail with timestamps added

Should be a bit more portable since echo -e/n and date's -Ins are not. Show Sample Output
This is sample output - yours may be different.
```
....
2010-11-24 05:46:58+0000        ##########
2010-11-24 05:46:59+0000        #  EOF   #
2010-11-24 05:46:59+0000        ##########
```
4

tail -f file | while read line; do printf "$(date -u '+%F %T%z')\t$line\n"; done

derekschrock · 2010-11-24 05:50:12 4
monitor a tail -f command with multiple processes

when using named pipes only one reader is given the output by default. Also, most commands piped to by grep use a buffer which save output until tail -f finishes, which is not convenient. Here, using a combination of tee, sub-processes and the --line-buffered switch in grep we can workaround the problem.
This is sample output - yours may be different.
4

tail -f somefile |tee >(grep --line-buffered '1' > one.txt) |tee >(grep --line-buffered '2' > two.txt)

binaryten · 2011-04-03 10:05:28 3
Tail a log-file over the network

This one is tried and tested for Ubuntu 12.04. Works great for tailing any file over http.
This is sample output - yours may be different.
4

(echo -e "HTTP/1.1 200 Ok\n\r"; tail -f /var/log/syslog) | nc -l 1234

adimania · 2013-02-09 06:15:42 5
View all new log messages in real time with color

This will show all changes in all log files under /var/log/ that are regular files and don't end with `gz` nor with a number Show Sample Output
This is sample output - yours may be different.
```
==> /var/log/auth.log <== 

==> /var/log/mail.log <== 

==> /var/log/auth.log <== 
Jul 29 19:07:30 yourhost sshd[7915]: Connection closed by 127.0.0.1 [preauth] 
```
4

find /var/log -type f -iregex '.*[^\.][^0-9]+$' -not -iregex '.*gz$' 2> /dev/null | xargs tail -n0 -f | ccze -A

rubo77 · 2014-07-29 17:11:17 5
Flush and then immediately start watching a file

This is useful for keeping an eye on an error log while developing. The !^ pulls the first arg from the previous command (which needs to be run in a sub-shell for this shortcut to work).
This is sample output - yours may be different.
3

(> errors.log) && tail -f !^

root · 2009-02-03 16:08:19 94
show all programs connected or listening on a network port

Use the aliased command 'nsl'
This is sample output - yours may be different.
3

alias nsl 'netstat -f inet | grep -v CLOSE_WAIT | cut -c-6,21-94 | tail +2'

mnikhil · 2009-02-07 18:54:12 10
List top 20 IP from which TCP connection is in SYN_RECV state

List top 20 IP from which TCP connection is in SYN_RECV state. Useful on web servers to detect a syn flood attack. Replace SYN_ with ESTA to find established connections Show Sample Output
This is sample output - yours may be different.
```
1 125.162.92.184
      1 125.164.121.250
      1 125.71.93.177
      1 128.107.229.110
      1 189.147.101.11
      1 202.40.210.145
      1 202.40.210.164
      1 203.130.201.198
      1 41.201.190.148
      1 41.201.238.148
      1 81.199.44.161
      1 81.202.11.253
      2 202.134.71.158
      7 218.4.59.190
```
3

netstat -pant 2> /dev/null | grep SYN_ | awk '{print $5;}' | cut -d: -f1 | sort | uniq -c | sort -n | tail -20

unixmonkey982 · 2009-02-16 08:49:38 245
Prints new content of files

Useful to e.g. keep an eye on several logfiles. Show Sample Output
This is sample output - yours may be different.
```
~$ tail -f file1 file2
==> file1 <==
==> file2 <==
==> file1 <==
new line in file1

==> file2 <==
new line in file2
```
3

tail -f file1 (file2 .. fileN)

hberth · 2009-03-02 11:13:42 7
Watch contents of a file grow

In this case, I'm keeping an eye on /var/log/messages, but of course any file will do. When I'm following a file, I generally don't want to see anything other than what has been added due to the command or service I've executed. This keeps everything clean and tidy for troubleshooting.
This is sample output - yours may be different.
3

tail -n 0 -f /var/log/messages

atoponce · 2009-03-02 14:21:18 11
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OSX command to take badly formatted xml from the clipboard, cleans it up and puts it back into the clipboard.

This command can be used with xclip or xsel for use on a linux box.

Execute a command on multiple hosts in parallel

Ssh to host1, host2, and host3, executing on each host and saving the output in {host}.log. I don't have the 'parallel' command installed, otherwise it sounds interesting and less cryptic.

Delete specific sender in mailq

ARP Scan

A much quicker and (not dirtier) option. use the man page for help. On linux/ubuntu you will need to `sudo apt-get -y install arp-scan`.

Change files case, without modify directories, recursively

Change files case, without modify directories, recursively. ... fucking vfat

In place line numbering

Add permanent line numbers to a file without creating a temp file. The rm command deletes file10 while the nl command works on the open file descriptor of file10 which it outputs into a new file again named file10. The new file10 will now be numbered in the same directory with the same file name and content as before, but it will in fact be a new file, using (ls -i) to show its inode number will prove this.

Easy way to scroll up und down to change to one of n last visited directories.

This alias is meant to append n (here is n=10) most recently used cd commands to the bottom of history file. This way you can easily change to one of previous visited directories simply by hitting 1-10 times arrow up key. Hint: You can make more aliases implying the same rule for any set of frequently used long and complex commands like: mkisof, rdesktop, gpg...

Colorized JSON pretty printing

Uses pygmentize and python to create indented and colorized JSON output

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Compare two directories

Output of this command is the difference of recursive file lists in two directories (very quick!). To view differences in content of files too, use the command submitted by mariusbutuc (very slow!): $ diff -rq path_to_dir1 path_to_dir2

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Commands using tail (292)

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