bash, extract string before a colon

Question

If I have a file with rows like this

/some/random/file.csv:some string
/some/random/file2.csv:some string2

Is there some way to get a file that only has the first part before the colon, e.g.

/some/random/file.csv
/some/random/file2.csv

I would prefer to just use a bash one liner, but perl or python is also ok.

Solution 1

cut -d: -f1

or

awk -F: '{print $1}'

or

sed 's/:.*//'

Solution 2

Another pure BASH way:

> s='/some/random/file.csv:some string'
> echo "${s%%:*}"
/some/random/file.csv

Solution 3

Try this in pure bash:

FRED="/some/random/file.csv:some string"
a=${FRED%:*}
echo $a

Here is some documentation that helps.

Solution 4

This works for me you guys can try it out

INPUT='ubuntu:x:1000:1000:Ubuntu:/home/ubuntu:/bin/bash'
SUBSTRING=$(echo $INPUT| cut -d: -f1)
echo $SUBSTRING

Solution 5

This has been asked so many times so that a user with over 1000 points ask for this is some strange
But just to show just another way to do it:

echo "/some/random/file.csv:some string" | awk '{sub(/:.*/,x)}1'
/some/random/file.csv

View more solutions

Comments

[chepner]

+1 (with a minor edit); this is the standard way to read delimited text from a file in bash.

[danday74]

awesome answer much appreciated

[mmoossen]

this does not work as expected if there are more than one colons in the variable, since it cuts at the last occurrence and not as expected the first... use <code>${s%%:*}<code> instead

[anubhava]

That's right %% will suit better. It is edited now.

[Victor Martinez]

This is exactly what I needed to list only the names of folders that changed in a git diff starting with a particular pattern

[siliconrockstar]

Lol I'm an idiot for forgetting about cut, just spent 10 minutes trying to do this regex and then literally facepalmed when I read your answer, thank you.

[Marco Martins]

Works for me to strip only the wanted info from a list of words, one at a time, with the format [info]_mapping.json. echo "${s%%_mapping.json}"

[Doktor J]

Note that a single % only extracts to the first colon; use %% to extract to the last colon.

[Rafael Beckel]

Actually, it's the opposite: %% extracts up to the first, % to the last.