this post was submitted on 22 Jun 2023
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cat vs sed vs awk (lemmy.sdf.org)
submitted 1 year ago* (last edited 1 year ago) by [email protected] to c/[email protected]
 
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[–] [email protected] 6 points 1 year ago

I feel like you can't compare these tools without talking about cut. I personally never use awk, but cut and other coreutils can be used together to achieve much of the same

[–] [email protected] 6 points 1 year ago* (last edited 1 year ago) (1 children)

love cat -n, when working with csv files I often use a command like this to figure out which column I need:

head -n1 file.csv | sed 's/,/\n/g' | cat -n

[–] [email protected] 2 points 1 year ago
[–] [email protected] 4 points 1 year ago

for me it's grep but i'm amazed how many searching tools there are on Linux. sed, grep, ripgrep, cat, find, walk, sor, locate, awk, etc.

[–] [email protected] 3 points 1 year ago

Okay, so cat is all I need, right?

...right?

[–] [email protected] 2 points 1 year ago

Thanks for the info!

[–] [email protected] 2 points 1 year ago

I pretty much always use these commands unless I need regex or something. I think it's a lot more maintainable by other people since awk and sed have their own unique syntax.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

cat
while read -r l; do echo "$l"; done <

cat -e
while read -r l; do echo "$l"$; done <

cat -n
n=0; while read -r l; do n="$((n+1))"; printf '%5d %s\n' "$n" "$l"; done <

cat -b
n=0; while read -r l; do [ -n "$l" ] && n="$((n+1))" && printf '%5d %s' "$n" "$l"; echo; done <

[–] [email protected] 0 points 1 year ago (1 children)
$ n=0; while read -r l; do n="$((n+1))" printf '    %d %s\n' "$n" "$l"; done < /etc/os-release 
    0 NAME="openSUSE Tumbleweed"
    0 # VERSION="20230619"
    0 ID="opensuse-tumbleweed"
 [...]
[–] [email protected] 1 points 1 year ago

; was missing

[–] [email protected] 1 points 1 year ago (1 children)

What is it you want to do?

[–] [email protected] 4 points 1 year ago (2 children)

just trying to get a good mental model of when it's reasonable to use tools like awk instead of simpler unix tools. also further confirming that sed is almost never the best tool except for substitutions.

[–] [email protected] 6 points 1 year ago (1 children)

Sed and awk have a lot of overlap. Another thing to consider is that neither might be the right choice if you are inside a bash script since spawning a new process in a tight loop can be very expensive and bash's built-in regex operations can have much better performance in those situations.

[–] [email protected] 2 points 1 year ago

That's a good point. If I need something like a bash script I tend to stick to bash features as much as possible.

[–] [email protected] 2 points 1 year ago

Ok, I would say... cat is mostly used for output of files, and concatenating files. sed and awk are good at reshaping the output of files or piped std input. They both require some time to learn, but it is worth going back to them.

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