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Replace lines in files with only spaces/tabs with simple empty line (within current directory - recursive)
This is sample output - yours may be different.
0

find . -type f -regex '.*\.$cpp\|h$' -exec sed -i 's/^[[:blank:]]\+$//g' {} \;

swarzynski · 2020-09-15 09:07:08 146
Find out how much ram memory has your video (graphic) card
This is sample output - yours may be different.
1

glxinfo |grep -i -o 'device|memory\|[0-9]\{1,12\} MB'|head -n 1

wuseman1 · 2020-09-14 02:12:47 774
find hard linked files (duplicate inodes) recursively

If you have two sets of files that may share hard-linked files, it can be useful to identify which ones are hard links to same underlying inode (file). This command shows you all of those, sorted by inode#. In my example the two directory trees to compare share a common parent, so I run the command in that parent and just use find . to start from the current directory. If yours are in different locations, you can pass both paths to find: find /directory1 /directory2 -type f -printf '%10i %p\n' | sort | uniq -w 11 -d -D | less Show Sample Output
This is sample output - yours may be different.
```
 190186228 ./10/alpha1/2612_fsm
 190186228 ./12/alpha1/base/19108/2612_fsm
 190203401 ./10/alpha1/pg_internal.init
 190203401 ./12/alpha1/base/19108/pg_internal.init
 190206322 ./10/alpha1/3079_fsm
 190206322 ./12/alpha1/base/19108/3079_fsm
```
0

find . -type f -printf '%10i %p\n' | sort | uniq -w 11 -d -D | less

dmmst19 · 2020-09-13 22:12:58 387
Find ASCII files and extract IP addresses
This is sample output - yours may be different.
2

find . -type f -exec grep -Iq . {} \; -exec grep -oE "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)" {} /dev/null \;

wuseman1 · 2020-09-13 03:06:22 307
Find out how much ram memory has your video (graphic) card

One liner is based on this article: https://www.computerhope.com/issues/ch001307.htm Show Sample Output
This is sample output - yours may be different.
```
$ lspci|grep -i "VGA Compatible Controller"|cut -d' ' -f1|xargs lspci -v -s|grep ' prefetchable'
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
```
-4

lspci|grep -i "VGA Compatible Controller"|cut -d' ' -f1|xargs lspci -v -s|grep ' prefetchable'

knoppix5 · 2020-09-11 14:04:10 274
Show which line of a shell script is currently executed

This way you don't need to replace first line of a bash foo.sh script #!/bin/bash with #!/bin/bash -x to obtain the same effect
This is sample output - yours may be different.
-1

bash -x foo.sh

knoppix5 · 2020-09-10 19:56:42 180
Learn the difference between single and double quotes
This is sample output - yours may be different.
4

a=7; echo $a; echo "$a"; echo '$a'; echo "'$a'"; echo '"$a"'

knoppix5 · 2020-09-10 02:47:40 212
Get an audio notification if a new device is attached to your computer

dmesg -t: no timestamp -W: follow new messages -l: log-level notice gawk if the fourth word is "Attached" echo a sentence through espeak
This is sample output - yours may be different.
0

dmesg -tW -l notice | gawk '{ if ($4 == "Attached") { system("echo New device attached | espeak") } }

BigZ · 2020-09-06 08:18:26 274
Tail a log and replace according to a sed pattern

Tails a log and replaces it line-by-line according to whatever you want to replace. Useful if the file writing to the log can't be modified, so you need to modify its output instead. Show Sample Output
This is sample output - yours may be different.
```
echo "line1
find
line2" >> logfile

Output:
line1
replace
line2
```
1

tail -F logfile|while read l; do sed 's/find/replace/g' <<< $l; done

tyzbit · 2020-08-07 12:26:39 453
Uniquely (sort of) color text so you can see changes

Colorify colors input by converting the text to a number and then performing modulo 7 on it. This resulting number is used as the color escape code. This can be used to color the results of commands with complex outputs (like "482279054165371") so if any of the digits change, there's a good chance the color will change too. I say good chance because there's only 7 unique colors here, so assuming you were watching random numbers, there would be a 6/7 chance that the color would change when the number changed. This should really only be used to help quickly identify when things change, but should not be the only thing relied upon to positively assert that an output has not changed. Show Sample Output
This is sample output - yours may be different.
```
$ colorify test
test (shows as orange)
$ colorify test2
test2 (shows as purple)
```
2

function colorify() { n=$(bc <<< "$(echo ${1}|od -An -vtu1 -w100000000|tr -d ' ') % 7"); echo -e "\e[3${n}m${1}\e[0m"; }

tyzbit · 2020-08-06 15:17:45 396
tar and bz2 a set of folders as individual files

This version will work if "*screenflow" returns any results with weird characters, and will actually compress the tarballs.
This is sample output - yours may be different.
3

find . -maxdepth 1 -type d -name '*screenflow' -exec tar jcvf {}.tar.bz2 {} \;

minnmass · 2020-08-02 22:34:14 141
tar and bz2 a set of folders as individual files

I use screenflow to create and edit videos. The default storage for a single video is a folder. If I want to move that someplace, it's easier to zip up the folder and send it. If I'm making a series of short videos, I might have 10 folders. This will go through and make a single bz3 file for EACH folder.
This is sample output - yours may be different.
0

for f in *screenflow ; do tar cvf "$f.tar.bz2" "$f"; done

topher1kenobe · 2020-08-02 21:10:27 162

List all accessed configuration files while executing a program in linux terminal (improved version)

Last listed files presumably have higher precedency then files listed first, i.e. configuration files in the personal .config directory will be listed last and their config parameters will be more authoritative then default config parameters defined in /etc directory which are usually listed above them. If you replace ".conf" with ".ini" in the command, initial files will be listed instead of config files. If you do not like to list multiple access to the same config file, pipe to "uniq" or "uniq -c" to prefix lines by the number of occurrences Show Sample Output

strace 2>&1 <any_executable> |egrep -o "\".*\.conf\""

knoppix5 · 2020-07-31 10:57:29 212

extract email addresses from some file (or any other pattern)
This is sample output - yours may be different.
1

grep -Eio '([[:alnum:]_.-]{1,64}@[[:alnum:]_.-]{1,252}?\.[[:alpha:].]{2,6})'

mikhail · 2020-07-22 22:40:33 138
Re-execute a command using a saved /proc/pid/cmdline file

Replace $CMDLINE_FILENAME with the name of the cmdline file you copied from /proc/pid, and $COMMAND with the command to execute with those arguments.
This is sample output - yours may be different.
-2

tail -zn+2 $CMDLINE_FILENAME | xargs -0 $COMMAND

Sparkette · 2020-06-23 05:31:45 122
create an uncompressed tar file of each child directory of the current working directory

First, use find to find directories exactly one level below current directory, then create a tar file using the directory as the basename.
This is sample output - yours may be different.
4

find . -maxdepth 1 -mindepth 1 -type d -exec tar cvf {}.tar {} \;

unixmonkey64021 · 2020-06-21 14:34:44 142
rclone - include Service account blobs to your config

For easy portability you can include you service account blobs directly to your rclone config. So it generate a rclone config like the following: [dst977] type = drive scope = drive service_account_credentials = {"type":"service_account","project_id":"saf-ju66hcgi8qf8zidhvfww4oxwe7","private[.................] } Show Sample Output
This is sample output - yours may be different.
```
[dst977]
type = drive
scope = drive
service_account_credentials = {"type":"service_account","project_id":"saf-ju66hcgi8qf8zidhvfww4oxwe7","private[.................] }
[dst978]
type = drive
scope = drive
service_account_credentials = {"type":"service_account","project_id":"saf-ju66hcgi8qf8zidhvfww4oxwe7","private[.................] }
[....]
```
1

bash -c 'COUNT=0; for i in $(find . -iname "*.json");do ((count=count+1));VAL=`cat ${i} | jq -c '.'` ; echo "[dst$count]";echo "type = drive";echo "scope = drive";echo "service_account_credentials = $VAL" ; echo "team_drive = 0AKLGAlhvkJYyUk9PVA" ;done'

dbiesecke · 2020-06-19 19:38:59 152
Login history Mac OS X

2d - is a shortcut for a period back in time Show Sample Output
This is sample output - yours may be different.
```
2020-05-28 21:49:37.140751+0200
2020-05-28 23:15:00.242348+0200
2020-05-29 11:20:36.974778+0200
2020-05-29 13:59:04.477616+0200
2020-05-29 15:11:21.299773+0200
2020-05-29 17:55:59.941100+0200
2020-05-30 09:12:55.268262+0200
```
0

% sudo log show --style syslog --last 2d | awk '/Enter/ && /unlockUIBecomesActive/ {print $1 " " $2}'

Repie · 2020-05-30 07:27:17 107
Before any Dell Firmware update on Ubuntu, run

After install https://linux.dell.com/repo/community/openmanage/ (Complete, all), install these packages or you will get segfaults on update and it will fail.
This is sample output - yours may be different.
0

apt install raidcfg dtk-scripts syscfg smbios-utils sfcb cim-schema dcism

pqatsi · 2020-05-29 06:49:23 158
emulate a root (fake) environment without fakeroot nor privileges
This is sample output - yours may be different.
0

unshare -r --fork --pid unshare -r --fork --pid --mount-proc bash

glaudiston · 2020-05-23 12:40:24 155
parse and format IP:port currently in listen state without net tools

Useful for containers and environments where you need to know if a port is currently in listen mode but you have not easy way or privileges to install net-tools like netstat or ss. "0A" is the code for listen state. The IP hex is reverse order and all in hex format. Show Sample Output
This is sample output - yours may be different.
```
0.0.0.0:111
10.174.109.1:53
127.0.0.53:53
0.0.0.0:22
127.0.0.1:631
0.0.0.0:8000
```
2

cat /proc/net/tcp | grep " 0A " | sed 's/^[^:]*: $..$$..$$..$$..$:$....$.*/echo $((0x\4)).$((0x\3)).$((0x\2)).$((0x\1)):$((0x\5))/g' | bash

glaudiston · 2020-05-23 12:36:21 152
Parse m3u playlist file for total time

Parse an m3u file with seconds for each item and output the length of the entire playlist Show Sample Output
This is sample output - yours may be different.
```
03:13:37
```
1

awk -F":|," '{RS="#"; sec+=$2}END{h=(sec/3600);m=((sec/60) % 60);s=(s;printf("%02d:%02d:%02d\n", h, m, s)}' file.m3u

jonavon · 2020-05-16 18:55:32 102
Fix time-stamped filenames of JPEG images according to the EXIF date the photo was taken

For each *.jpg or *.JPG file in the current directory, extract the date the photo was taken from its EXIF metadata. Then replace the date stamp, which is assumed to exist in the filename, by the date the photo was taken. A trick from https://unix.stackexchange.com/a/9256 is used to split the date into its components. Show Sample Output
This is sample output - yours may be different.
```
'2020-04-12 DSC_0146.JPG' -> '2017-12-26 DSC_0146.JPG'
'2020-04-12 DSC_0147.JPG' -> '2017-12-28 DSC_0147.JPG'
```
0

(IFS=': '; for i in *.(#i)jpg; do set $(exiv2 -K 'Exif.Image.DateTime' -Pv $i 2> /dev/null); mv -v $i "$1-$2-$3${i#[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]}"; done)

langec · 2020-05-16 12:10:00 126
Generates a TV noise alike output in the terminal

Generates a TV noise alike output in the terminal. Can be combined with https://www.commandlinefu.com/commands/view/9728/make-some-powerful-pink-noise
This is sample output - yours may be different.
7

while true;do printf "$(awk -v c="$(tput cols)" -v s="$RANDOM" 'BEGIN{srand(s);while(--c>=0){printf("\xe2\x96\\%s",sprintf("%o",150+int(10*rand())));}}')";done

ichbins · 2020-05-08 09:55:36 210
Check if port is open on remote machine

Check if port is open, if you don't have ncat on your machine. Show Sample Output
This is sample output - yours may be different.
```
Port is open
```
6

echo > /dev/tcp/127.0.0.123/8085 && echo "Port is open"

jonavon · 2020-05-03 13:30:13 459
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ssh -A user@somehost

the -A argument forwards your ssh private keys to the host you're going to. Useful in some scenarios where you have to hop to one server, and then login to another using a private key.

sends your internal IP by email

This is useful if you have need to do port forwarding and your router doesn't assign static IPs, you can add it to a script in a cron job that checks if you IP as recently changed or with a trigger script. This was tested on Mac OSX.

list block devices

Shows all block devices in a tree with descruptions of what they are.

Colored diff ( via vim ) on 2 remotes files on your local computer.

You can use $ vim scp://root@example.com//file too in a simple case.

Find out current working directory of a process

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" }

Find usb device

I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

recursively change file name from uppercase to lowercase (or viceversa)

Example of zsh globing, glob qualifier, and substitution: -Q state that the parameter will contain a glob qualifier. (**/)(*) is recursive (.) is our glob qualifier, with states the match is a file "." The first parameter $1, is then substituted with $2 but with lowercasing '(L)' ... a (U) would of course be from lower to upper.

convert from hexidecimal or octal to decimal

Bash can accept '0x' and '0' notation for hexidecimal and octal numbers, so you just have to output the values.

Extract audio from a video

With the -vn switch we make our intentions clear and ask FFmpeg not to bother itself with the video. Next we specify the audio codec copy, which tells FFmpeg to use the same codec to encode the audio, which it uses to decode it. To keep things simple, we'll just keep the sampling and bitrate values the same.

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