Commands by axelabs

Commands by axelabs (11)

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Use the builtin ':' bash command to increment variables

I just found another use for the builtin ':' bash command. It increments counters for me in a loop if a certain condition is met... : [arguments] No effect; the command does nothing beyond expanding arguments and performing any specified redirections. A zero exit code is returned. Show Sample Output
This is sample output - yours may be different.
```
1
```
2

[ $V ] || : $((V++)) && echo $V

axelabs · 2012-06-15 16:48:03 0
Synchronize directory copy

rsync will copy the source directory into destination and any subsequent run will synchronize only the changes from the source. Show Sample Output
This is sample output - yours may be different.
```
building file list ... done
src/
src/modified
src/newfile

sent 271 bytes  received 70 bytes  682.00 bytes/sec
total size is 30  speedup is 0.09
```
0

rsync -avz ~/src ~/des/

axelabs · 2012-06-01 15:08:12 2
Time conversion/format using the date command

Show Sample Output
This is sample output - yours may be different.
```
epoch: 1323946029 or format: 2011/12/15
```
1

date -d '2011-12-15 05:47:09' +"epoch: %s or format: %Y/%m/%d"

axelabs · 2011-12-16 18:43:36 0
Identifying Xorg video driver in use

The above one liner can be used to determine what card/driver is Xorg currently using. For additional information, see http://goo.gl/mDnWu Show Sample Output
This is sample output - yours may be different.
```
[    27.597] (II) RADEON(0): PCIE card detected
[    27.638] (II) RADEON(0): Output LVDS connected
```
-1

egrep -i " connected|card detect|primary dev" /var/log/Xorg.0.log

axelabs · 2011-02-24 18:04:04 0
Use tee to process a pipe with two or more processes

Tee can be used to split a pipe into multiple streams for one or more process to work it. You can add more " >()" for even more fun. Show Sample Output
This is sample output - yours may be different.
```
tee can split a pipe in two
tee_can_split_a_pipe_in_two
owt ni epip a tilps nac eet
```
33

echo "tee can split a pipe in two"|tee >(rev) >(tr ' ' '_')

axelabs · 2010-08-14 20:38:59 3
Sed can refference parts of the pattern in the replacement:

Show Sample Output
This is sample output - yours may be different.
```
me=swap
2=1
```
2

echo -e "swap=me\n1=2"|sed 's/$.*$=$.*$/\2=\1/g'

axelabs · 2010-01-16 22:01:37 0
Watch number of lines being processed on a clear screen

awk can clear the screen while displaying output. This is a handy way of seeing how many lines a tail -f has hit or see how many files find has found. On solaris, you may have to use 'nawk' and your machine needs 'tput' Show Sample Output
This is sample output - yours may be different.
```
13164
```
0

cat /dev/urandom|awk 'BEGIN{"tput cuu1" | getline CursorUp; "tput clear" | getline Clear; printf Clear}{num+=1;printf CursorUp; print num}'

axelabs · 2009-07-13 07:30:51 0
Randomize lines in a file

This appends a random number as a first filed of all lines in SOMEFILE then sorts by the first column and finally cuts of the random numbers.
This is sample output - yours may be different.
4

awk 'BEGIN{srand()}{print rand(),$0}' SOMEFILE | sort -n | cut -d ' ' -f2-

axelabs · 2009-05-29 01:20:50 4
lsof equivalent on solaris

Report fstat(2) and fcntl(2) information for all open files in each process.
This is sample output - yours may be different.
4

/usr/proc/bin/pfiles $PID

axelabs · 2009-03-05 17:26:57 2
Print text string vertically, one character per line.

Show Sample Output
This is sample output - yours may be different.
```
P
r
i
n
t
 
t
e
x
t
 
v
e
r
t
i
c
a
l
l
y
```
8

echo Print text vertically|sed 's/$.$/\1\n/g'

axelabs · 2009-03-04 23:58:02 6
check if commandlinefu.com got a better domain

It would be nice if commandlinefu.com had a better domain name. Will they pick one of the above; We'll see. Show Sample Output
This is sample output - yours may be different.
```
No whois server is known for this kind of object.
No match for "CMDFU.COM".
```
-11

whois cmd.fu;whois cmdfu.com|grep -i cmdfu

axelabs · 2009-02-19 08:57:50 3

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Mute speakers after an hour

Mutes the speakers after an hour, in case you fall asleep watching a video...

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"

Scan for new SCSI devices

Issues a scan command on the given scsi host adapter (ex. a fibre channel adapter, in the example above on host0). Output can be watched in the messages log or in "dmesg"

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"

Printable random characters

Reads psuedorandom bytes from /dev/urandom, filtering out non-printable ones. Other character classes can be used, such as [:alpha:], [:digit:] and [:alnum:]. To get a string of 10 lowercase letters: $ tr -dc '[:lower:]' < /dev/urandom | head -c 10

Simplest way to get size (in bytes) of a file

Match a URL

For the record: I didn't build this. Just shared what I found that worked. Apologies to the original author! I decided I should fix the case where http://example.com is not matched for the next time I need this. So I read rfc1035 and formalized the host name regex. If anyone finds any more holes, please comment.

Change mysql prompt to be more verbose

You can put this into your shell sourced file like .bashrc or .zshrc to have a different mysql prompt. See http://dev.mysql.com/doc/refman/5.1/de/mysql-commands.html for more informations. Beware that currently with mysql 5.5 the seconds are buggy and won't be displayed if you put this into a .cnf file. With the enironment variable this will work.

Rip a video for archiving, from any site

Download video files from a bunch of sites (here is a list https://rg3.github.io/youtube-dl/supportedsites.html). The options say: base filename on title, ignores errors and continue partial downloads. Also, stores some metadata into a .json file plz. Paste youtube users and playlists for extra fun. Protip: git-annex loves these files

Are the two lines anagrams?

This works by reading in two lines of input, turning each into a list of one-character matches that are sorted and compared.

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