head -10 file
File cutting summary
line oriented
-
to keep the first 10 lines of "file":
-
to skip the first 10 lines of "file":
tail +11 file
-
to skip the last 10 lines of "file":
head -n -10 file
-
to keep the last 10 lines of "file":
tail -10 file
-
to print lines 11-20 of a file:
sed -e 1,10d -e 20q file
-
to cut lines by criteria, use 'grep', 'grep -v' or 'sed'.
-
to cut a file into pieces, use split
byte oriented
-
Use head to keep the first 50m
head -c 50m
-
to skip the first several bytes using dd
$ seq 5 | dd ibs=1 skip=6 4 5 4+0 records in 0+1 records out
-
to skip the last 50m
head -c -50m
column oriented
use cut.
documented on: 2007.04.11
cmd:head
head
head -c 50m
Help
-n, --lines=[-]N print the first N lines instead of the first 10;
with the leading `-', print all but the last
N lines of each file
-c, --bytes=[-]N print the first N bytes of each file;
with the leading `-', print all but the last
N bytes of each file
SIZE may have a multiplier suffix: b for 512, k for 1K, m for 1 Meg.
head or tail
> > Is there any ready-made tool to print lines from a file *after* a given > > line number?
Well, tail does that just fine; to skip the first 10 lines of "file":
tail +11 file
Another option is sed:
sed 1,10d file
The sed approach generizes better; to print lines 11-20 of a file:
sed -e 1,10d -e 20q file
-Ken Pizzini
head or tail
All lines after line 10:
sed -n '11,$ p' <infile
Ken
documented on: 07-19-99
cmd:cut
Usage
ff -l . | cut -c1-12,29-
ls -l | cut -c30-42,56-
head /usr/X11R6/lib/X11/rgb.txt | cut -f 3 # X ls -l | cut -d ' ' -f 1,9 # not working!
Help
-c list The list following -c specifies character posi-
tions (for instance, -c1-72 would pass the first
72 characters of each line).
|
Starting from 1. |
-f, --fields field-list
Print only the fields listed in field-list. Fields are sepa-
rated by a TAB by default.
-d, --delimiter delim
For -f, fields are separated by the first character in delim
instead of by TAB.
|
|
-d 'x' would normally always follows -f, |
choosing the fields
cut -d':' -f 2
$ cut -d: -f1,5 /etc/passwd | head root:Super-User daemon: adm:Admin lp:Line Printer Admin smtp:Mail Daemon User uucp:uucp Admin
|
|
-d ' ' is not good. |
It can't imitate the awk field selection: Better use -c to pick out the range if you can.
How to eliminate 1 column
Newsgroups: comp.unix.shell
> > I need to eliminate the second column of a certain file. > > Sounds like a job for cut.
Only if the columns are delimited by *exactly one* space. If they look like:
Margolin Barry Other stuff Doherty John More other stuff
then cut by itself is useless. You could, however, use sed to collapse all the spaces into a single space and then pipe that to cut.
Barry Margolin
