This is a list of linux commands for common operations.
Note items marked with • are valid/safe to paste without modification into a terminal, so
you may want to keep a terminal window open while reading this so you can cut & paste.
Original site is http://www.pixelbeat.org/cmdline.html

CommandDescription
apropos wordShow commands pertinent to word. See also threadsafe
 which commandShow full path name of command
 time commandSee how long a command takes
time catStart stopwatch. Ctrl-d to stop. See also sw
nice infoRun a low priority command (info in this case)
renice 19 -p $$Make shell (script) low priority. Use for non interactive tasks
look prefixQuickly search (sorted) dictionary
grep --color expr...ion /usr/share/dict/wordsHighlight occurances of regular expression in dictionary
 gpg -c fileEncrypt file
 gpg file.gpgDecrypt file
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 $USERSearch current environment
ls /usr/bin | pr -T9 -W$COLUMNSPrint in 9 columns to width of terminal
 touch -c -t 0304050607 fileSet file timestamp (YYMMDDhhmm)
dir navigation
cd -Go to previous directory
cdGo 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
CDs
 gzip < /dev/cdrom > cdrom.iso.gzSave copy of data cdrom
 mkisofs -V NAME -r dir | gzip > cdrom.iso.gzCreate cdrom image from contents of dir
 mount -o loop cdrom.iso /mnt/dirMount the cdrom image at /mnt/dir (read only)
 cdrecord -v dev=/dev/cdrom blank=fastClear a CDRW
 gzip -dc cdrom.iso.gz | cdrecord -v dev=/dev/cdrom -Burn cdrom image (use dev=ATAPI -scanbus to confirm dev)
 cdparanoia -BRip audio tracks from CD to wav files in current dir
 cdrecord -v dev=/dev/cdrom -audio *.wavMake 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
archives
 tar c dir/ | bzip2 > dir.tar.bz2Make archive of dir/
 bzip2 -dc dir.tar.bz2 | tar xExtract archive (use gzip instead of bzip2 for tar.gz files)
 tar c dir/ | gzip | gpg -c | ssh user@remote 'dd of=dir.tar.gz.gpg'Make encrypted archive of dir/ on remote machine
 find dir/ -name '*.txt' | tar c --files-from=- | bzip2 > dir_txt.tar.bz2Make archive of subset of dir/ and below
 find dir/ -name '*.txt' | xargs cp -a --target-directory=dir_txt/ --parentsMake copy of subset 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/ && tar x -p )Copy (with permissions) contents of copy/ dir to /where/to/
 ( tar c /dir/to/copy ) | ssh -C user@remote 'cd /where/to/ && tar x -p' Copy (with permissions) copy/ dir to remote:/where/to/ dir
 dd bs=1M if=/dev/hda | gzip | ssh user@remote 'dd of=hda.gz'Backup harddisk to remote machine
rsync (Use the --dry-run option for testing)
 rsync -P rsync://rsync.server.com/path/to/file fileOnly get diffs. Do multiple times for troublesome downloads
 rsync --bwlimit=1000 fromfile tofileLocally copy with rate limit. It's like nice for I/O
 rsync -az -e ssh --delete ~/public_html/ remote.com:'~/public_html'Mirror web site (using compression and encryption)
 rsync -auz -e ssh remote:/dir/ . && rsync -auz -e ssh . remote:/dir/Synchronize current directory with remote one
alias l='ls -l --color=auto'quick dir listing
ls -lrtList files by date. See also newest
 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 'string'Search all regular files for 'string' in this dir and below
 find -maxdepth 1 -type f | xargs grep -F 'string'Search all regular files for 'string' in this dir
 find -maxdepth 1 -type d | while read dir; do echo $dir; echo cmd2; doneProcess each item with multiple commands (in while loop)
find -type f ! -perm -444Find files not readable by all (useful for web site)
find -type d ! -perm -111Find 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
networking (Note ifconfig, route, mii-tool, nslookup commands are obsolete)
ip link showList interfaces
 ethtool interfaceList interface status
 ip link set dev eth0 name wanRename eth0 to wan
 ip addr add 1.2.3.4/24 brd + dev eth0Add ip and mask(255.255.255.0)
 ip link set dev interface upBring interface up (or down)
 ip route add default via 1.2.3.254Set default gateway to 1.2.3.254
tc qdisc add dev lo root handle 1:0 netem delay 20msecAdd 20ms latency to loopback device (for testing)
tc qdisc del dev lo rootRemove latency added above
host pixelbeat.orgLookup ip address for name or vice versa
hostname -iLookup local ip address (equivalent to host `hostname`)
netstat -tuplList internet services on a system
netstat -tupList active connections to/from system
wget (multi purpose download tool)
(cd cmdline && wget -nd -pHEKk http://www.pixelbeat.org/cmdline.html) Store local browsable version of a page to the current dir
 wget -c http://www.example.com/large.fileContinue downloading a partially downloaded file
 wget -r -nd -np -l1 -A '*.jpg' http://www.example.com/Download a set of 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 | grep 'a href' | headProcess output directly
 echo 'wget url' | at 01:00Download url at 1AM to current dir
 wget --limit-rate=20k urlDo a low priority download (limit to 20KB/s in this case)
 wget -nv --spider --force-html -i bookmarks.htmlCheck links in a file
 wget --mirror http://www.example.com/Efficiently update a local copy of a site (handy from cron)
windows (note samba is the package that provides all this windows specific networking support)
smbtreeFind windows machines. See also findsmb
 nmblookup -A 1.2.3.4Find the windows (netbios) name associated with ip address
 smbclient -L windows_boxList shares on windows machine or samba server
 mount -t smbfs -o fmask=666,guest //windows_box/share /mnt/shareMount a windows share
 echo 'message' | smbclient -M windows_boxSend popup to windows machine (off by default in XP sp2)
math
echo '(1 + sqrt(5))/2' | bc -lQuick math (Calculate φ)
echo 'obase=16; ibase=10; 123' | bcBase conversion (decimal to hexadecimal)
echo $((0x2dec))Base conversion (hex to dec) ((shell arithmetic expansion))
echo 'pad=20; min=64; (100*10^6)/((pad+min)*8)' | bcMore complex (int) e.g. This shows max FastE packet rate
echo 'pad=20; min=64; print (100E6)/((pad+min)*8)' | pythonPython handles scientific notation
echo 'pad=20; plot [64:1518] (100*10**6)/((pad+x)*8)' | gnuplot -persistPlot FastE packet rate vs packet size
seq 100 | (tr '\n' +; echo 0) | bcAdd a column of numbers. See also add and funcpy
text manipulation (note sed uses stdin and stdout, so if you want to edit files, append <oldfile >newfile)
 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
 sed -n '1000p;1000q'Print 1000th line
 sed -n '10,20p;20q'Print lines 10 to 20
 sed -n 's/.*<[tT][iI][tT][lL][eE]>\(.*\)<\/[tT][iI][tT][lL][eE]>.*/\1/p;T;q'Extract title from HTML web page
 sort -t. -k1,1n -k2,2n -k3,3n -k4,4nSort IPV4 ip addresses
echo 'Test' | tr '[:lower:]' '[:upper:]'Case conversion
tr -dc '[:print:]' < /dev/urandomFilter non printable characters
grep 'processor' /proc/cpuinfo | wc -lCount lines
set operations (Note LANG=C is for speed) (Note also these assume no duplicate lines within a file)
 LANG=C sort file1 file2 | uniqUnion of unsorted files
 LANG=C sort file1 file2 | uniq -dIntersection of unsorted files
 LANG=C sort file1 file1 file2 | uniq -uDifference of unsorted files
 LANG=C sort file1 file2 | uniq -uSymmetric Difference of unsorted files
 LANG=C comm file1 file2 | sed 's/^\t*//'Union of sorted files
 LANG=C comm -12 file1 file2Intersection of sorted files
 LANG=C comm -13 file1 file2Difference of sorted files
 LANG=C comm -3 file1 file2 | sed 's/^\t*//'Symmetric Difference of sorted files
calendar
cal -3Display a calendar
cal 9 1752Display a calendar for a particular month year
date -d friWhat date is it this friday. See also day
date --date='25 Dec' +%AWhat day does xmas fall on, this year
date --date '1970-01-01 UTC 1234567890 seconds'Convert number of seconds since the epoch to a date
TZ=':America/Los_Angeles' dateWhat time is it on West coast of US (use tzselect to find TZ)
 echo "mail -s 'get the train' P@draigBrady.com < /dev/null" | at 17:45Email reminder
echo "DISPLAY=$DISPLAY xmessage cooker" | at "NOW + 30 minutes"Popup reminder
locales
printf "%'d\n" 1234Print number with thousands grouping appropriate to locale
echo "I live in `locale territory`"Extract info from locale database
locale | cut -d= -f1 | xargs locale -kc | lessList fields in locale database
LANG=en_IE.utf8 locale int_prefixLookup locale info for specific country. See also ccodes
disk space (See also FSlint)
ls -lSrShow files, biggest last
du -s * | sort -k1,1rn | headShow top disk users in current dir. See also dutop
df -hShow free disk space
df -iShow free inodes
fdisk -lShow disks partitions sizes and types (run as root)
rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1nList all packages by installed size (Bytes) on rpm distros
dpkg-query -W -f='${Installed-Size;10}\t${Package}\n' | sort -k1,1nList all packages by installed size (KBytes) on deb distros
dd bs=1 seek=2TB if=/dev/null of=ext3.testCreate a large test file (taking no space). See also truncate
monitoring/debugging
strace -c ls >/dev/nullSummarise/profile system calls made by command
strace -f -e open ls >/dev/nullList system calls made by command
ltrace -f -e getenv ls >/dev/nullList 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 22Show network traffic except ssh. See also tcpdump_not_me
ps -e -o pid,args --forestList processes in a hierarchy
ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed '/^ 0.0 /d'List processes by % cpu usage
ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNSList processes by mem usage. See also ps_mem.py
ps -C firefox-bin -L -o pid,tid,pcpu,stateList all threads for a particular process
ps -p 1,2List info for particular process IDs
last rebootShow system reboot history.
free -mShow amount of (remaining) RAM (-m displays in MB)
watch -n1 'cat /proc/interrupts'Watch changeable data continuously
System information (see also sysinfo)
 hdparm -i /dev/hdaShow info about disk hda
 hdparm -tT /dev/hdaDo a read speed test on disk hda
 badblocks -s /dev/hdaTest for unreadable blocks on disk hda
mount | column -tShow mounted filesystems on the system (and align output)
cat /proc/partitionsShow all partitions registered on the system
grep MemTotal /proc/meminfoShow RAM total seen by the system
grep "model name" /proc/cpuinfoShow CPU(s) info
lspci -tvShow PCI info
lsusb -tvShow USB info
recode (Obsoletes iconv, dos2unix, unix2dos)
recode -l | lessShow available conversions (aliases on each line)
 recode windows-1252.. file_to_change.txtWindows "ansi" to local charset (auto does CRLF conversion)
 recode utf-8/CRLF.. file_to_change.txtWindows utf8 to local charset
 recode iso-8859-15..utf8 file_to_change.txtLatin9 (western europe) to utf8
 recode ../b64 < file.txt > file.b64Base64 encode
 recode /qp.. < file.txt > file.qpQuoted printable decode
 recode ..HTML < file.txt > file.htmlText to HTML
recode -lf windows-1252 | grep euroLookup table of characters
echo -n 0x80 | recode latin-9/x1..dumpShow what a code represents in latin-9 charmap
echo -n 0x20AC | recode ucs-2/x2..latin-9/xShow latin-9 encoding
echo -n 0x20AC | recode ucs-2/x2..utf-8/xShow utf-8 encoding
interactive
mcPowerful filemanager that can browse rpm, tar, ftp, ssh, ...
screenVirtual terminals with detach capability, ...
linksWeb browser
gnuplotInteractive/scriptable graphing
octaveMatlab like environment