Updated: 01.07.2021
Send mail from command line (Postfix configured):
$ date | mail -s "Postfix test" my.email@domain.com
List directories and files that don’t have default permissions and ignore .git subfolder:
$ find . ! -path "./.git/*" -type d ! -perm 644 -o -type f ! -perm 755
Get disk identifier:
$ diskutil list
APFS
Output example:
...
2: Apple_APFS Container disk1 49.2 GB disk0s2
...
Resize partition to 60 GB:
$ diskutil apfs resizeContainer disk0s2 60g
HFS+
...
2: Apple_HFS Macintosh HD 30.0 GB disk1s2
...
$ diskutil resizeVolume disk1s2 50G
Resize partition to it’s maximum size:
$ diskutil resizeVolume disk1s2 R
screen commands.Start new screen session:
screen
Detach from the current session:
ctrl + a > d
Attach to a previous session:
screen -r
List sessions:
screen -ls
Quit session:
ctrl + a > :quit
Source file contains multiple dates as one date / line.
Old format: 20-08-2015
New format: 20150820
Convert all dates to new format:
k=0; while read line; do let k+=1; echo $line | awk -v FS=- -v OFS= '{print $3,$2,$1}'; done < old_dates.txt > new_dates.txt
Replace tabs with spaces:
:set list
:set tabstop=4 shiftwidth=4 expandtab
:retab
Replace Windows line feeds with UNIX line feeds:
:%s/^M/\r/g
Use ag to find .download.recipe files that don’t contain codesignatureverifier string:
$ ag -G ".download.recipe$" -ilv codesignatureverifier path/to/recipes
Find last 5 photos & videos imported from Nikon (DSC_XXXX.JPG/MOV):
$ find . -type f -iname "DSC_*" -print0 | xargs -0 stat -f "%m %Sm %SN" -t "%d.%m.%Y %H:%M" | sort -nr | cut -d " " -f 2- | head -5
Example output:
24.02.2015 19:27 ./Kuvat ja videot/Kuvat/2015/2015-02-kuvat/DSC_3143.JPG
15.02.2015 09:10 ./Kuvat ja videot/Kuvat/2015/2015-02-kuvat/DSC_3140.JPG
15.02.2015 09:10 ./Kuvat ja videot/Kuvat/2015/2015-02-kuvat/DSC_3139.JPG
09.01.2015 17:49 ./Kuvat ja videot/Kuvat/2015/2015-01-kuvat/DSC_3138.JPG
09.01.2015 17:48 ./Kuvat ja videot/Videot/2015/2015-01-videot/DSC_3137.MOV
List of modified files from the past 7 days (excluding Dropbox cache + .DS_Store and Icon? files):
$ find . -type f ! -path "./.dropbox.cache/*" ! -name ".DS_Store" ! -name "Icon?" -mtime -7 -print0 | xargs -0 stat -f "%m %Sm %SN" -t "%d.%m.%Y %H:%M" | sort -nr | cut -d " " -f 2-
Sample output:
...
15.03.2015 12:14 ./path/to/1.jpg
15.03.2015 12:13 ./path/to/2.jpg
15.03.2015 12:11 ./path/to/1.txt
15.03.2015 12:10 ./path/to/2.txt
...
Copy GoPro photos & videos from the past 7 days to Dropbox Camera Uploads folder:
$ find ~/Pictures/GoPro/ -mtime -7 \( -iname "*.MP4" -o -iname "*.JPG" \) -exec cp -pvn {} ~/Dropbox/Camera\ Uploads \;
Change file extension from .log to .txt:
$ for file in *.log; do mv -i "$file" "${file%.log}.txt"; done
Replace Photo with Pic:
$ for file in Photo*; do mv -i "$file" "${file/#Photo/Pic}"; done
Replace Photo*.png with 2014_[digit].png:
$ d=0; for file in Photo*; do let d+=1; mv -i "$file" 2014_$d.png; done
Same as previous but with one leading zero:
$ d=0; for file in Photo*; do let d+=1; mv -i "$file" 2014_$(printf "%02d\n" $d).png; done
Remove 12 characters before file extension from a file name:
for file in *.mp4; do mv -i "$file" "${file%%????????????.mp4}.mp4"; done
Example:
Some youtube video (episode 1)-RiTAdApC5-Y.mp4 => Some youtube video (episode 1).mp4
Generate SSH key pair using ed25519 algorithm:
$ ssh-keygen -a 100 -t ed25519 -f path/to/<some>.key -C "<description>"
List top 10 user names used in SSH break-in attempts:
macOS 10.12+
$ log show --info --last 24h | grep -o "Invalid user.*" | awk '{print $3}' | sort | uniq -c | sort -nr | head -10
macOS 10.11 and earlier
$ grep -o "Invalid user.*" /var/log/system.log | awk '{print $3}' | sort | uniq -c | sort -nr | head -10
List successful SSH logins using public key method:
macOS 10.12+
$ log show --info --last 24h | grep "Accepted publickey"
macOS 10.11 and earlier
$ grep "Accepted publickey" /var/log/system.log
Strip code signing information from profile:
$ security cms -D -i Signed.mobileconfig -o Unsigned.mobileconfig
Ignore warning message:
security: SecPolicySetValue: One or more parameters passed to a function were not valid.
Reindent a xml/plist/mobileconfig file:
$ xmllint --format original.mobileconfig > modified.mobileconfig
Combined:
$ security cms -D -i Signed.mobileconfig | xmllint --format - > Unsigned.mobileconfig
Current SSID name:
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I | grep -w "SSID" | awk -F": " '{print $2}'
Get weekday for certain date:
$ date -jf "%d.%m.%Y" "30.07.2010" +%A
Mount encrypted (sparse disk) image:
$ hdiutil attach -stdinpass /path/to/image.dmg
Search directories recursively for files matching ‘string’:
$ grep -r -l 'string' /path/to/dir
Show original file location if symlink:
$ readlink /tmp
Use multicast address to find out all multicast capable hosts:
$ ping 224.0.0.1
List unique IP addresses in Apache access log:
$ cat /var/log/apache2/access_log | awk '{print $2}' | sort | uniq -c | sort -nr
Number of unique IP addresses in Apache access log:
$ cat /var/log/apache2/access_log | awk '{print $2}' | sort | uniq -c | wc -l
List macOS installer package bill of materials:
$ lsbom -p MUGsf /path/to/Archive.bom
If flat package, first expand the package contents to a temp folder:
$ pkgutil --expand /path/to/installer.pkg ~/Desktop/temp_out
Show used disk space on boot volume (total):
$ df -h / | awk 'NR > 1 {print $3}'