Linux less command: scroll back to show text files
Linux less command Function Description
The less command is very similar to the more command in that it can be used to view the contents of a text file, except that the less command allows the user to scroll back.
Linux less command syntax
less [Option] [File]
The meaning of each option in the command is shown in the table.
- -b
Set the size of the buffer - -e Automatically leave when the document display is finished
- -f Force open special files such as peripheral designators, directories and binary files
- -g Only the last searched keyword is flagged
- -i Ignore case in search
- -m Show percentages similar to the more command
- -N Display the line number of each line
- -o
Save the less output in the specified file - -Q No warning tone
- -s Show consecutive blank lines
- -S The line is too long to discard the excess
- -x
Display the "tab" key as the specified number of spaces - /String: Search "String" function down
- ?String: Upward search function for "string"
- n: Repeat the previous search (with / or ?) related)
- N: Repeat the previous search in reverse (with / or ?) related)
- b: Turn up a page
- d: Turn back half a page
- h: Show help screen
- Q Exit the less command
- u Scroll forward half a page
- y Scroll forward one line
- Spacebar Scroll down a page
- Enter key Scroll a line
- [pagedown] Scroll down one page
- [pageup] Flip up one page
Linux less command Demo
Rollback to show the contents of the /etc/services file
[root@rhel ~]# less /etc/services
# /etc/services:
# Id: services, v 1.482009/11/11 14:32:31 ovasik Exp
#
# Network services, Internet style
# IANA services version: last updated 2009-11-10
#
# Note that it is presently the policy of IANA to assign a single well-known
# port number for both TCP and UDP; hence, most entries here have two entries
# even if the protocol doesn't support UDP operations.
#Updated from RFC 1700, ''Assigned Numbers''(October 1994). Not all ports
# are included, only the more common ones.
#
# The latest IANA port assignments can be gotten from
# http://www.iana.org/assignments/port-numbers
# The Well Known Ports are those from 0 through 1023.
# The Registered Ports are those from 1024 through 49151
# The Dynamic and/or Private Ports are those from 49152 through 65535
#
# Each line describes one service, and is of the form:
#
#service-name port/protocol [aliases...] [#comment]
tcpmux 1/tcp #TCP port service multiplexer
tcpmux 1/udp #TCP port service multiplexer
rje 5/tcp #Remote Job Entry
rje 5/udp #Remote Job Entry
echo 7/tcp
echo 7/udp
discard 9/tcp sink null
discard 9/udp sink null
systat 11/tcp users
systat 11/udp users
daytime 13/tcp
daytime 13/udp
qotd 17/tcp quote
qotd 17/udp quote
msp 18/tcp #message send protocol
msp 18/udp #message send protocol
/etc/services
ps view process information and paginate it with less
ps -ef |less
View command history and display by less paging
[root@localhost test]# history | less
22 scp -r tomcat6.0.32 root@192.168.120.203:/opt/soft
23 cd ..
24 scp -r web root@192.168.120.203:/opt/
25 cd soft
26 ls
…………