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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Generic shell function for modifying files in-place

Some commands (such as sed and perl) have options to support in-place editing of files, but many commands do not. This shell function enables any command to change files in place. See the sample output for many examples. The function uses plain sh syntax and works with any POSIX shell or derivative, including zsh and bash.

Getting information about model no. of computer

This command gives a model information of a computer. Also useful in determining the host is a VM machine or actual physical machine.

Install pip with Proxy

Installs pip packages defining a proxy

Convert seconds to [DD:][HH:]MM:SS

Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

du and sort to find the biggest directories in defined filesystem

This command give a human readable result without messing up the sorting.

Apply substitution only on the line following a marker

I've been auto-generating some complex GnuPlots; with multiplots the first plot of each group needs to be a 'plot' whereas the others need to be 'replots' to allow overplotting/autoscaling/etc to work properly. This is used to replace only the first instance of 'replot'.

download and unpack tarball without leaving it sitting on your hard drive

Find usb device in realtime

Using this command you can track a moment when usb device was attached.

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"

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

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