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Earlier quoted context omitted.
Or, at least when running Bash (possibly sh, didn't try), just >foo also works to create file "foo".
That does not work, but :>foo (the happy file creation operator) does.
Also ":>" is not an operator, it's ":" (a built-in command that does nothing and returns true) and a redirection.
Instead of using a cat with heredoc, just type cat - | grep "something" And control-d when finished entering text
cat | grep "something"cat > file vs. touch file cat file | cmd vs. cmd So even some of the thing listed are still not the best use case for cat
| cat > file vs. touch file With 'cat > file' you can actually type in the file's contents (then press ^d to finish). 'touch file' merely creates an empty file. (Not that I think 'cat > file' is much faster than 'vi file')
Of course when having some text cat > file is just fine.
ps has a nasty habit of truncating its output. Piping it into cat is a way around this. E.G. $ echo $COLUMNS 118 $ ps -fp 14706 UID PID PPID C STIME TTY TIME CMD root 14706 14705 0 Jan29 pts/3 00:00:00 sudo -p [local sudo] Password: python /usr/lib/sshuttle/main.py pytho $ ps -fp 14706 | cat UID PID PPID C STIME TTY TIME CMD root 14706 14705 0 Jan29 pts/3 00:00:00 sudo -p [local sudo] Password: python /usr/lib/sshutt…
To see which columns a particular value occurs in:
awk -F'\t' You may also create new empty files by saying `touch filename`. This saves three keystrokes (which includes an annoying `>` symbol, requiring the shift key) as compared to the aforementioned `cat` method!
Don't forget "tac" - the reverse of "cat".
The real opposite of cat would be a putative 'trunc'. So if you typed
$ cat somefile
$ trunc somefile
You may also create new empty files by saying `touch filename`. This saves three keystrokes (which includes an annoying `>` symbol, requiring the shift key) as compared to the aforementioned `cat` method!
what do you mean? "cat > file" allows you to create simple text file not just empty files. As long as you don't need advanced editing, it is the quickest way to do it (well I think).
cat > file vs. touch file cat file | cmd vs. cmd So even some of the thing listed are still not the best use case for cat
It does make things less efficient of course, as there is at least one extra memory-copy of everything and extra process context switching, but in most cases your drives or network are the bottleneck not CPU speed or memory bandwidth. Also, when working on the command line you can drop in useful tools like pv in place of cat.