System Manager

Command Description

. apropos whatis Show commands

pertinent to string.

See also threadsafe

. man -t man ps2pdf - > man.pdf make a pdf of a

manual page

which command Show full path name

of command

time command See how long a

command takes

. time cat Start stopwatch.

Ctrl-d to stop. See

also sw

. nice info Run a low priority

command (The "info"

reader in this case)

. renice 19 -p $$ Make shell (script)

low priority. Use

for non interactive

tasks

dir navigation

. cd - Go to previous

directory

. cd Go to $HOME

directory

(cd dir && command) Go to dir, execute

command and return

to current dir

. pushd . Put current dir on

stack so you can

popd back to it

file searching

. alias l='ls -l --color=auto' quick dir listing

. ls -lrt List files by date.

See also newest and

find_mm_yyyy

. ls /usr/bin pr -T9 -W$COLUMNS Print in 9 columns

to width of terminal

find -name ch]' xargs grep -E 'expr' Search 'expr' in

this dir and below.

See also findrepo

find -type f -print0 xargs -r0 grep -F 'example' Search all regular

files for 'example'

in this dir and

below

find -maxdepth 1 -type f xargs grep -F 'example' Search all regular

files for 'example'

in this dir

find -maxdepth 1 -type d while read dir; do echo Process each item

$dir; echo cmd2; done with multiple

commands (in while

loop)

. find -type f ! -perm -444 Find files not

readable by all

(useful for web

site)

. find -type d ! -perm -111 Find dirs not

accessible by all

(useful for web

site)

. locate -r 'file txt' Search cached index

for names. This re

is like glob

*file*.txt

. look reference Quickly search

(sorted) dictionary

for prefix

. grep --color reference /usr/share/dict/words Highlight occurances

of regular

expression in

dictionary

archives and compression

gpg -c file Encrypt file

gpg file.gpg Decrypt file

tar -c dir/ bzip2 > dir.tar.bz2 Make compressed

archive of dir/

bzip2 -dc dir.tar.bz2 tar -x Extract archive (use

gzip instead of

bzip2 for tar.gz

files)

tar -c dir/ gzip gpg -c ssh user@remote 'dd Make encrypted

of=dir.tar.gz.gpg' archive of dir/ on

remote machine

find dir/ -name '*.txt' tar -c --files-from=- bzip2 Make archive of

> dir_txt.tar.bz2 subset of dir/ and

below

find dir/ -name '*.txt' xargs cp -a Make copy of subset

--target-directory=dir_txt/ --parents of dir/ and below

( tar -c /dir/to/copy ) ( cd /where/to/ && tar -x -p Copy (with

) permissions) copy/

dir to /where/to/

dir

( cd /dir/to/copy && tar -c . ) ( cd /where/to/ && Copy (with

tar -x -p ) permissions)

contents of copy/

dir to /where/to/

( tar -c /dir/to/copy ) ssh -C user@remote 'cd Copy (with

/where/to/ && tar -x -p' permissions) copy/

dir to

remote:/where/to/

dir

dd bs=1M if=/dev/sda gzip ssh user@remote 'dd Backup harddisk to

of=sda.gz' remote machine

rsync (Network efficient file copier: Use the --dry-run option for testing)

rsync -P rsync://rsync.server.com/path/to/file file Only get diffs. Do

multiple times for

troublesome

downloads

rsync --bwlimit=1000 fromfile tofile Locally copy with

rate limit. It's

like nice for I/O

rsync -az -e ssh --delete ~/public_html/ Mirror web site

remote.com public_html' (using compression

and encryption)

rsync -auz -e ssh remote:/dir/ . && rsync -auz -e ssh . Synchronize current

remote:/dir/ directory with

remote one

ssh (Secure SHell)

ssh $USER@$HOST command Run command on $HOST

as $USER (default

command=shell)

. ssh -f -Y $USER@$HOSTNAME xeyes Run GUI command on

$HOSTNAME as $USER

scp -p -r $USER@$HOST: file dir/ Copy with

permissions to

$USER's home

directory on $HOST

ssh -g -L 8080:localhost:80 root@$HOST Forward connections

to $HOSTNAME:8080

out to $HOST:80

ssh -R 1434:imap:143 root@$HOST Forward connections

from $HOST:1434 in

to imap:143

wget (multi purpose download tool)

cd dir/ && wget -nd -pHEKk Store local

http://www.pixelbeat.org/cmdline.html) browsable version of

a page to the

current dir

wget -c http://www.example.com/large.file Continue downloading

a partially

downloaded file

wget -r -nd -np -l1 -A '*.jpg' Download a set of

http://www.example.com/dir/ files to the current

directory

wget ftp://remote/file[1-9].iso/ FTP supports

globbing directly

. wget -q -O- http://www.pixelbeat.org/timeline.html Process output

grep 'a href' head directly

echo 'wget url' at 01:00 Download url at 1AM

to current dir

wget --limit-rate=20k url Do a low priority

download (limit to

20KB/s in this case)

wget -nv --spider --force-html -i bookmarks.html Check links in a

file

wget --mirror http://www.example.com/ Efficiently update a

local copy of a site

(handy from cron)

networking (Note ifconfig, route, mii-tool, nslookup commands are obsolete)

ethtool eth0 Show status of

ethernet interface

eth0

ethtool --change eth0 autoneg off speed 100 duplex full Manually set

ethernet interface

speed

iwconfig eth1 Show status of

wireless interface

eth1

iwconfig eth1 rate 1Mb/s fixed Manually set

wireless interface

speed

. iwlist scan List wireless

networks in range

. ip link show List network

interfaces

ip link set dev eth0 name wan Rename interface

eth0 to wan

ip link set dev eth0 up Bring interface eth0

up (or down)

. ip addr show List addresses for

interfaces

ip addr add 1.2.3.4/24 brd + dev eth0 Add (or del) ip and

mask (255.255.255.0)

. ip route show List routing table

ip route add default via 1.2.3.254 Set default gateway

to 1.2.3.254

. tc qdisc add dev lo root handle 1:0 netem delay 20msec Add 20ms latency to

loopback device (for

testing)

. tc qdisc del dev lo root Remove latency added

above

. host pixelbeat.org Lookup DNS ip

address for name or

vice versa

. hostname -i Lookup local ip

address (equivalent

to host `hostname`)

. whois pixelbeat.org Lookup whois info

for hostname or ip

address

. netstat -tupl List internet

services on a system

. netstat -tup List active

connections to/from

system

windows networking (Note samba is the package that provides all this windows

specific networking support)

. smbtree Find windows

machines. See also

findsmb

nmblookup -A 1.2.3.4 Find the windows

(netbios) name

associated with ip

address

smbclient -L windows_box List shares on

windows machine or

samba server

mount -t smbfs -o fmask=666,guest //windows_box/share Mount a windows

/mnt/share share

echo 'message' smbclient -M windows_box Send popup to

windows machine (off

by default in XP

sp2)

text manipulation (Note sed uses stdin and stdout. Newer versions support

inplace editing with the -i option)

sed 's/string1/string2/g' Replace string1 with

string2

sed 's/\ 1/\12/g' Modify anystring1 to

anystring2

sed '/ *#/d; /^ *$/d' Remove comments and

blank lines

sed ':a; N; s n//; ta' Concatenate lines

with trailing \

sed 's/[ \t Remove trailing

spaces from lines

sed 's/\ 1/g' Escape shell

metacharacters

active within double

quotes

. seq 10 sed "s/^/ /; s/ 7 1/" Right align numbers

sed -n '1000{p;q}' Print 1000th line

sed -n '10,20p;20q' Print lines 10 to 20

sed -n 's title>\ <\/title 1/ip;T;q' Extract title from

HTML web page

sed -i 42d ~/.ssh/known_hosts Delete a particular

line

sort -t. -k1,1n -k2,2n -k3,3n -k4,4n Sort IPV4 ip

addresses

. echo 'Test' tr '[:lower:]' '[:upper:]' Case conversion

. tr -dc '[:print:]' < /dev/urandom Filter non printable

characters

. history wc -l Count lines

set operations (Note you can export LANG=C for speed. Also these assume no

duplicate lines within a file)

sort file1 file2 uniq Union of unsorted

files

sort file1 file2 uniq -d Intersection of

unsorted files

sort file1 file1 file2 uniq -u Difference of

unsorted files

sort file1 file2 uniq -u Symmetric Difference

of unsorted files

join -t'\0' -a1 -a2 file1 file2 Union of sorted

files

join -t'\0' file1 file2 Intersection of

sorted files

join -t'\0' -v2 file1 file2 Difference of sorted

files

join -t'\0' -v1 -v2 file1 file2 Symmetric Difference

of sorted files

math

. echo '(1 + sqrt(5))/2' bc -l Quick math

(Calculate ?). See

also bc

. echo 'pad=20; min=64; (100*10^6 pad+min)*8)' bc More complex (int)

e.g. This shows max

FastE packet rate

. echo 'pad=20; min=64; print (100E6 pad+min)*8)' Python handles

python scientific notation

. echo 'pad=20; plot [64:1518] (100*10**6 pad+x)*8)' Plot FastE packet

gnuplot -persist rate vs packet size

. echo 'obase=16; ibase=10; 64206' bc Base conversion

(decimal to

hexadecimal)

. echo $((0x2dec)) Base conversion (hex

to dec) ((shell

arithmetic

expansion))

. units -t '100m/9.58s' 'miles/hour' Unit conversion

(metric to imperial)

. units -t '500GB' 'GiB' Unit conversion (SI

to IEC prefixes)

. units -t '1 googol' Definition lookup

. seq 100 (tr '\n' +; echo 0) bc Add a column of

numbers. See also

add and funcpy

calendar

. cal -3 Display a calendar

. cal 9 1752 Display a calendar

for a particular

month year

. date -d fri What date is it this

friday. See also day

$(date -d "tomorrow" +%d) = "01" ] exit exit a script unless

it's the last day of

the month

. date --date='25 Dec' +%A What day does xmas

fall on, this year

. date --date='@214-***-****' Convert seconds

since the epoch

(1970-01-01 UTC) to

date

. TZ='America/Los_Angeles' date What time is it on

west coast of US

(use tzselect to

find TZ)

. date --date='TZ="America/Los_Angeles" 09:00 next Fri' What's the local

time for 9AM next

Friday on west coast

US

echo "mail -s 'get the train' abl1ym@r.postjobfree.com < Email reminder

/dev/null" at 17:45

. echo "DISPLAY=$DISPLAY xmessage cooker" at "NOW + 30 Popup reminder

minutes"

locales

. printf "%'d\n" 1234 Print number with

thousands grouping

appropriate to

locale

. BLOCK_SIZE=\'1 ls -l get ls to do

thousands grouping

appropriate to

locale

. echo "I live in `locale territory`" Extract info from

locale database

. LANG=en_IE.utf8 locale int_prefix Lookup locale info

for specific

country. See also

ccodes

. locale cut -d= -f1 xargs locale -kc less List fields

available in locale

database

recode (Obsoletes iconv, dos2unix, unix2dos)

. recode -l less Show available

conversions (aliases

on each line)

recode windows-1252.. file_to_change.txt Windows "ansi" to

local charset (auto

does CRLF

conversion)

recode utf-8/CRLF.. file_to_change.txt Windows utf8 to

local charset

recode iso-8859-15..utf8 file_to_change.txt Latin9 (western

europe) to utf8

recode ../b64 < file.txt > file.b64 Base64 encode

recode /qp.. < file.qp > file.txt Quoted printable

decode

recode ..HTML < file.txt > file.html Text to HTML

. recode -lf windows-1252 grep euro Lookup table of

characters

. echo -n 0x80 recode latin-9/x1..dump Show what a code

represents in

latin-9 charmap

. echo -n 0x20AC recode ucs-2/x2..latin-9/x Show latin-9

encoding

. echo -n 0x20AC recode ucs-2/x2..utf-8/x Show utf-8 encoding

CDs

gzip < /dev/cdrom > cdrom.iso.gz Save copy of data

cdrom

mkisofs -V LABEL -r dir gzip > cdrom.iso.gz Create cdrom image

from contents of dir

mount -o loop cdrom.iso /mnt/dir Mount the cdrom

image at /mnt/dir

(read only)

cdrecord -v dev=/dev/cdrom blank=fast Clear a CDRW

gzip -dc cdrom.iso.gz cdrecord -v dev=/dev/cdrom - Burn cdrom image

(use dev=ATAPI

-scanbus to confirm

dev)

cdparanoia -B Rip audio tracks

from CD to wav files

in current dir

cdrecord -v dev=/dev/cdrom -audio -pad *.wav Make audio CD from

all wavs in current

dir (see also

cdrdao)

oggenc --tracknum='track' track.cdda.wav -o 'track.ogg' Make ogg file from

wav file

disk space (See also FSlint)

. ls -lSr Show files by size,

biggest last

. du -s * sort -k1,1rn head Show top disk users

in current dir. See

also dutop

. df -h Show free space on

mounted filesystems

. df -i Show free inodes on

mounted filesystems

. fdisk -l Show disks

partitions sizes and

types (run as root)

. rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' sort -k1,1n List all packages by

installed size

(Bytes) on rpm

distros

. dpkg-query -W -f Installed-Size;10}\t${Package}\n' List all packages by

sort -k1,1n installed size

(KBytes) on deb

distros

. dd bs=1 seek=2TB if=/dev/null of=ext3.test Create a large test

file (taking no

space). See also

truncate

file truncate data of

file or create an

empty file

monitoring/debugging

. tail -f /var/log/messages Monitor messages in

a log file

. strace -c ls >/dev/null Summarise/profile

system calls made by

command

. strace -f -e open ls >/dev/null List system calls

made by command

. ltrace -f -e getenv ls >/dev/null List library calls

made by command

. lsof -p $$ List paths that

process id has open

. lsof ~ List processes that

have specified path

open

. tcpdump not port 22 Show network traffic

except ssh. See also

tcpdump_not_me

. ps -e -o pid,args --forest List processes in a

hierarchy

. ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu List processes by %

sed '/^ 0.0 /d' cpu usage

. ps -e -orss=,args= sort -b -k1,1n pr -TW$COLUMNS List processes by

mem (KB) usage. See

also ps_mem.py

. ps -C firefox-bin -L -o pid,tid,pcpu,state List all threads for

a particular process

. ps -p 1,2 List info for

particular process

IDs

. last reboot Show system reboot

history

. free -m Show amount of

(remaining) RAM (-m

displays in MB)

. watch -n.1 'cat /proc/interrupts' Watch changeable

data continuously

system information (see also sysinfo) means root access is required)

. uname -a Show kernel version

and system

architecture

. head -n1 /etc/issue Show name and

version of

distribution

. cat /proc/partitions Show all partitions

registered on the

system

. grep MemTotal /proc/meminfo Show RAM total seen

by the system

. grep "model name" /proc/cpuinfo Show CPU(s) info

. lspci -tv Show PCI info

. lsusb -tv Show USB info

. mount column -t List mounted

filesystems on the

system (and align

output)

. grep -F capacity: /proc/acpi/battery/BAT0/info Show state of cells

in laptop battery

# dmidecode -q less Display SMBIOS/DMI

information

# smartctl -A /dev/sda grep Power_On_Hours How long has this

disk (system) been

powered on in total

# hdparm -i /dev/sda Show info about disk

sda

# hdparm -tT /dev/sda Do a read speed test

on disk sda

# badblocks -s /dev/sda Test for unreadable

blocks on disk sda

interactive (see also linux keyboard shortcuts)

. readline Line editor used by

bash, python, bc,

gnuplot, ...

. screen Virtual terminals

with detach

capability, ...

. mc Powerful file

manager that can

browse rpm, tar,

ftp, ssh, ...

. gnuplot Interactive/scriptab

le graphing

. links Web browser

. xdg-open . open a file or url

with the registered

desktop application

miscellaneous

. alias hd='od -Ax -tx1z -v' Handy hexdump.

(usage e.g.: . hd

/proc/self/cmdline

less)

. alias realpath='readlink -f' Canonicalize path.

(usage e.g.: .

realpath USER)

. set grep $USER Search current

environment

touch -c -t 030******* file Set file timestamp

(YYMMDDhhmm)

. python -m SimpleHTTPServer Serve current

directory tree at

http HOSTNAME:800

0/

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