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Mithil Poojary
Mithil Poojary

Posted on • Updated on

6 Unix tools you need to know about

1. column

I, as a programmer, do not mind those nastily formatted tabular data, like...

Pid Name %CPU
1230 Firefox 15
600 Code 12
809 Terminal 1.2
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But when I learnt about column, I was pretty fascinated by how easy it is to make it neat!

column <file_name> -t

Pid   Name       %CPU
1230  Firefox    15
600   Code       12
809   Terminal  1.2
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2. less

How many times did you feel disgusted by the mess you made on your terminal screen? Maybe you printed a huge file or did ps aux. I have been there.
A very neat solution is to use less. The text is displayed upon applying a filter for paging through text one screenful at a time.

You don't have any clutter on your terminal once you exit less.

3. sort

Imagine having a file with ID and Names like this.

16  Siri
20  Cortana
13  Mithil
9   Jarvis
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A quick sort on the IDs would be super helpful right?

sort <file_name> -n

9   Jarvis
13  Mithil
16  Siri
20  Cortana
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4. tr

I can't really think of a better situation to use this right now, but hey it works.
Say you have to replace the occurence of a character. tr (translate) does this for you.

echo "This is a sentence" | tr " " "\n"

This
is
a
sentence
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5. head and tail

Head and tail themselves are pretty solid tools, but together they have their own use case.

Say you want the 11th line in a text file. You can do this by :

head <file_name> -n 11 | tail -n 1
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That was all for this post. What are your preferred helpful Unix tools?

Photo by Karl Pawlowicz on Unsplash

Top comments (5)

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_garybell profile image
Gary Bell

I'm a huge fan of the (relatively) straight forward find command. When coupled with -exec, you can do some pretty creative things, fairly quickly.

I've used find historically for getting backup files which are more than 2 weeks old, and deleting them. It's a simple way of keeping backups from taking over hard drive space, without needing to do everything manually

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geekypandey profile image
Anurag Pandey

That coupling with exec takes it to another level. What are your other favourites?

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_garybell profile image
Gary Bell

Going to be boring and say grep. I think a lot of people have it as a go-to tool to filter the returned output of a command into something useful.

I don't spend a lot of time in the terminal using Linux/Unix specific commands. Most of my time on the terminal is spend using Git, and increasingly more often, redis-cli

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geekypandey profile image
Anurag Pandey

Yeah. git grep is super handy to find files with particular snippets of code.

I started with competitive programming recently and I used to save code as filename.py and then testcase_filename for the testcases. ls | grep -v testcase came in handy to code files and clear the noise.

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josephj11 profile image
Joe

I don't use tr very often, but it's very handy for getting rid of odd binary codes in text files and translating between upper and lower case. I have seen much fancier uses of it, but don't recall any at the moment.

Here's a quick way to show someone the format of a data file without revealing any sensitive data.

#!/bin/bash
## Obsfucate a text file
## 11/25/2013
## Thanks to D. Joe on the WNYLUG list
## For sharing the format of a text file with sensitive data in it

if [ -z "${1}" ]
then
  IN="/dev/stdin"
else
  if [ ! -r "${1}" ]
  then
    echo "Can't read [${1}]"
    exit 1
  fi

  IN="${1}"
fi

if [ -z "${2}" ]
then
  OUT="/dev/stdout"
else
  OUT="${2}"
fi

tr 'a-z' 'A-Z' < "${IN}" | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'AAAAAAAAAAAAAAAAAAAAAAAAAA' | tr '0123456789' '9999999999' > "${OUT}"

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