Intro To 'numfmt' Command In Linux

2024-06-01 - By Robert Elder

     I use the 'numfmt' command to format numbers that quantify data storage:

echo '1024' | numfmt

1024

echo '1024' | numfmt --to=si

1.1K

echo '1024' | numfmt --to=iec

1.0K

echo '1024' | numfmt --to=iec-i

1.0Ki

A Real-World Use Case

     Recently, my YouTube shorts videos haven't been doing well:

     Kids these days just aren't interested in the same old boring output from the 'ls' command:

ls -l

total 108
-rw-rw-r-- 1 robert robert 54957 May 27 22:58 cat.png
-rw-rw-r-- 1 robert robert 44824 May 27 22:58 main.c
-rw-rw-r-- 1 robert robert  4324 May 27 22:58 README.txt

     But I can use the 'numfmt' command to format the output of my commands in such a way that appeals to terminally online people who are obsessed with memes and anime culture:

ls -l | numfmt --field=5 --format="💗UωU💗 %4f 🥺👉👈"

total 108
-rw-rw-r-- 1 robert robert 💗UωU💗 54957 🥺👉👈 May 27 22:58 cat.png
-rw-rw-r-- 1 robert robert 💗UωU💗 44824 🥺👉👈 May 27 22:58 main.c
-rw-rw-r-- 1 robert robert 💗UωU💗 4324 🥺👉👈 May 27 22:58 README.txt

     The '--format' flag allows me to specify how the size quantity is represented, and the '--field' flag specifies which columns are to be formatted.

Format Sizes In SI or IEC Representation

     I can also use the '--to' flag to represent the file size in SI, IEC or two letter IEC representation:

numfmt --from=si --to=iec 1M

977K

numfmt --from=si --to=iec 1048576

1.0M

Format Arbitrary Size Quantities

     The 'numfmt' command can also accept optional numbers as input as well:

numfmt --from=si --to=iec 1Z

868E

numfmt --from=si --to=iec 1E

889P

numfmt --from=si --to=iec 1P

910T

numfmt --from=si --to=iec 1T

932G

numfmt --from=si --to=iec 1G

954M

numfmt --from=si --to=iec 1M

977K

numfmt --from=si --to=iec 1K

1000

     This can be useful for performing inline unit conversions.

     Now, all the people with anime profile pictures will press the like button on my videos, and I'll become YouTube famous:

     And that's why the 'numfmt' command is my favourite Linux command.