cat is misunderstood a lot. The purpose of cat is to combine multiple files together (it’s literally short for “concatenate”), like cat *.log to combine all log files together.
If you’re just using it for a single file, then you should just redirect the file to stdin. These two command lines behave similarly:
cat foo.txt | some-command
some-command < foo.txt
For head, tail, grep and some other commands, you can just pass in the file name directly as an argument (e.g. grep whatever foo.txt).
I still like doing cat file.txt | grep thing because I often re-run it to find something else like cat file.txt | grep thing2 - and if I do that with grep, the pattern sits awkwardly in the middle instead of at the end
You’ll see cat FILE | all the time because it’s just a natural start to a pipeline. You cat FILE to see the content unfiltered before filtering it with further commands.
catis misunderstood a lot. The purpose of cat is to combine multiple files together (it’s literally short for “concatenate”), likecat *.logto combine all log files together.If you’re just using it for a single file, then you should just redirect the file to stdin. These two command lines behave similarly:
cat foo.txt | some-commandsome-command < foo.txtFor
head,tail,grepand some other commands, you can just pass in the file name directly as an argument (e.g.grep whatever foo.txt).Fair, but in general I find it way more useful to use cat for piping.
In most cases I’ll do something like
cat file | program cat file | program | grep cat file | program | grep | cutThis gets more complicated if the file is at the end of the command.
It wouldn’t be at the end, since you’d still be piping into
programprogram <file | grep | cutAnd
<file program | grep | cutworks tooThanks - I didn’t know this either!
Oh, thanks! Didn’t know that
I still like doing
cat file.txt | grep thingbecause I often re-run it to find something else likecat file.txt | grep thing2- and if I do that with grep, the pattern sits awkwardly in the middle instead of at the end< file.txt grep thingalso works.You’ll see
cat FILE |all the time because it’s just a natural start to a pipeline. Youcat FILEto see the content unfiltered before filtering it with further commands.Also known as cat abuse.
awww what’s a cat without a head and a tail?
I guess depending on your interpretation of without it could either be “cat” or “a”.
A kernel?
uhmm no
If I just want to look at the file, is there a better way than
cat foo.txt? I guess I can’t just do< foo.txtYou can use
less. There are also specialized ones for that purpose like bat.Admittedly I still use
catfor this.This also works too, but it’s more verbose:
echo "$(<foo.txt)"It’s mentioned in the Bash man pages:
So close! you have to do
cat < foo.txt:-) (/s)yeah sure but the command is literally written for the humor.
I know, but I just wanted to mention this since a lot of new Linux users end up using cat this way :)
Is there any downside?
ohhh but it’s all humor that’s the point of the post.
I mean as a new Linux user, I won’t take anything from a humor group seriously.