Linux command (like cat) to read a specified quantity of characters

Question

Is there a command like cat in linux which can return a specified quantity of characters from a file?

e.g., I have a text file like:

Hello world
this is the second line
this is the third line

And I want something that would return the first 5 characters, which would be "hello".

thanks

Answer 1

head or tail can do it as well:

head -c X

Prints the first X bytes (not necessarily characters if it's a UTF-16 file) of the file. tail will do the same, except for the last X bytes.

This (and cut) are portable.

Answer 2

head works too:

head -c 100 file  # returns the first 100 bytes in the file

..will extract the first 100 bytes and return them.

What's nice about using head for this is that the syntax for tail matches:

tail -c 100 file  # returns the last 100 bytes in the file

Answer 3

you could also grep the line out and then cut it like for instance:

grep 'text' filename | cut -c 1-5

Answer 4

You can use dd to extract arbitrary chunks of bytes.

For example,

dd skip=1234 count=5 bs=1

would copy bytes 1235 to 1239 from its input to its output, and discard the rest.

To just get the first five bytes from standard input, do:

dd count=5 bs=1

Note that, if you want to specify the input file name, dd has old-fashioned argument parsing, so you would do:

dd count=5 bs=1 if=filename

Note also that dd verbosely announces what it did, so to toss that away, do:

dd count=5 bs=1 2>&-

or

dd count=5 bs=1 2>/dev/null

Answer 5

head -Line_number file_name | tail -1 |cut -c Num_of_chars

this script gives the exact number of characters from the specific line and location, e.g.:

head -5 tst.txt | tail -1 |cut -c 5-8

gives the chars in line 5 and chars 5 to 8 of line 5,

Note: tail -1 is used to select the last line displayed by the head.