| | Commands
| Description |
| 1 | apropos whatis
| Show commands pertinent to string. See also threadsafe |
| 2 | man -t man | ps2pdf - > man.pdf | make a pdf of a manual page |
| 3 | which command | Show full path name of command |
| 4 | time command | See how long a command takes |
| 5 | time cat | Start stopwatch. Ctrl-d to stop.
|
| 6 | nice info | Run a low priority command (The "info" reader in this case) |
| 7 | renice 19 -p $$ | Make shell (script) low priority. Use for non interactive tasks |
| | Dir Navigation
| |
| 1 | cd -
| Go to previous directory |
| 2 | cd | Go to $HOME directory |
| 3 | (cd dir && command) | Go to dir, execute command and return to current dir |
| 4 | pushd . | Put current dir on stack so you can popd back to i |
| | File search
| |
| 1 | alias l='ls -l --color=auto' | quick dir listing |
| 2 | ls -lrt | List files by date.
|
| 3 | ls /usr/bin | pr -T9 -W$COLUMNS | Print in 9 columns to width of terminal |
| 4 | find -name '*.[ch]' | xargs grep -E 'expr' | Search 'expr' in this dir and below. |
5
| find -type f -print0 | xargs -r0 grep -F 'example' | Search all regular files for 'example' in this dir and below |
6
| find -maxdepth 1 -type f | xargs grep -F 'example' | Search all regular files for 'example' in this dir |
| 7 | find -maxdepth 1 -type d | while read dir; do echo $dir; echo cmd2; done | Process each item with multiple commands (in while loop) |
| 8 | find -type f ! -perm -444 | Find files not readable by all (useful for web site) |
| 8 | find -type d ! -perm -111 | Find dirs not accessible by all (useful for web site) |
| 9 | locate -r 'file[^/]*\.txt' | Search cached index for names. This re is like glob *file*.txt |
| 10 | look reference | Quickly search (sorted) dictionary for prefix |
| 11 | grep --color reference /usr/share/dict/words | Highlight occurances of regular expression in dictionary |
| | archives and compression | |
| 1 | gpg -c file | Encrypt file |
| 2 | gpg file.gpg | Decrypt file |
| 3 | tar -c dir/ | bzip2 > dir.tar.bz2 | Make compressed archive of dir/ |
| 4 | bzip2 -dc dir.tar.bz2 | tar -x | Extract archive (use gzip instead of bzip2 for tar.gz files) |
| 5 | tar -c dir/ | gzip | gpg -c | ssh user@remote 'dd of=dir.tar.gz.gpg' | Make encrypted archive of dir/ on remote machine |
| 6 | find dir/ -name '*.txt' | tar -c --files-from=- | bzip2 > dir_txt.tar.bz2 | Make archive of subset of dir/ and below |
| 7 | find dir/ -name '*.txt' | xargs cp -a --target-directory=dir_txt/ --parents | Make copy of subset of dir/ and below |
| 8 | (tar -c /dir/to/copy ) | ( cd /where/to/ && tar -x -p ) | Copy (with permissions) copy/ dir to /where/to/ dir |
| 9 | (cd /dir/to/copy && tar -c . ) | ( cd /where/to/ && tar -x -p ) | Copy (with permissions) contents of copy/ dir to /where/to/ |
| 10 | ( 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 |
| 11 | dd bs=1M if=/dev/sda | gzip | ssh user@remote 'dd of=sda.gz' | Backup harddisk to remote machine |
| | rsync (Network efficient file copier: Use the --dry-run option for testing) | |
| 1 | rsync -P rsync://rsync.server.com/path/to/file file | Only get diffs. Do multiple times for troublesome downloads |
| 2 | rsync --bwlimit=1000 fromfile tofile | Locally copy with rate limit. It's like nice for I/O |
| 3 | rsync -az -e ssh --delete ~/public_html/ remote.com:'~/public_html' | Mirror web site (using compression and encryption) |
| 4 | rsync -auz -e ssh remote:/dir/ . && rsync -auz -e ssh . remote:/dir/ | Synchronize current directory with remote one |
| | ssh (Secure SHell) | |
| 1 | ssh $USER@$HOST command | Run command on $HOST as $USER (default command=shell) |
| 2 | ssh -f -Y $USER@$HOSTNAME xeyes | Run GUI command on $HOSTNAME as $USER |
| 3 | scp -p -r $USER@$HOST: file dir/ | Copy with permissions to $USER's home directory on $HOST |
| 4 | ssh -g -L 8080:localhost:80 root@$HOST | Forward connections to $HOSTNAME:8080 out to $HOST:80 |
| 5 | ssh -R 1434:imap:143 root@$HOST | Forward connections from $HOST:1434 in to imap:143 |
| | wget (multi purpose download tool) | |
| 1 | (cd dir/ && wget -nd -pHEKk http://www.pixelbeat.org/cmdline.html) | Store local browsable version of a page to the current dir |
| 2 | wget -c http://www.example.com/large.file | Continue downloading a partially downloaded file |
| 3 | wget -r -nd -np -l1 -A '*.jpg' http://www.example.com/dir/ | Download a set of files to the current directory |
| 4 | wget ftp://remote/file[1-9].iso/ | FTP supports globbing directly |
| 5 | wget -q -O- http://www.pixelbeat.org/timeline.html | grep 'a href' | head | Process output directly |
| 6 | echo 'wget url' | at 01:00 | Download url at 1AM to current dir |
| 7 | wget --limit-rate=20k url | Do a low priority download (limit to 20KB/s in this case) |
| 8 | wget -nv --spider --force-html -i bookmarks.html | Check links in a file |
| 9 | 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) | |
| 1 | ethtool eth0 | Show status of ethernet interface eth0 |
| 2 | ethtool --change eth0 autoneg off speed 100 duplex full | Manually set ethernet interface speed |
| 3 | iwconfig eth1 | Show status of wireless interface eth1 |
| 4 | iwconfig eth1 rate 1Mb/s fixed | Manually set wireless interface speed |
| 5 | iwlist scan | List wireless networks in range |
| 6 | ip link show | List network interfaces |
| 7 | ip link set dev eth0 name wan | Rename interface eth0 to wan |
| 8 | ip link set dev eth0 up | Bring interface eth0 up (or down) |
| 9 | ip addr show | List addresses for interfaces
|
| 10 | ip addr add 1.2.3.4/24 brd + dev eth0 | Add (or del) ip and mask (255.255.255.0) |
| 11 | ip route show | List routing table |
| 12 | ip route add default via 1.2.3.254 | Set default gateway to 1.2.3.254 |
| 13 | tc qdisc add dev lo root handle 1:0 netem delay 20msec | Add 20ms latency to loopback device (for testing) |
| 14 | tc qdisc del dev lo root | Remove latency added above |
| 15 | host gnugroup.org
| Lookup DNS ip address for name or vice versa |
| 16 | hostname -i | Lookup local ip address (equivalent to host `hostname`)
|
| 17 | whois gnugroup.org | Lookup whois info for hostname or ip address |
| 18 | netstat -tupl | List internet services on a system |
| 19 | netstat -tup | List active connections to/from system |
| | windows networking (Note samba is the package that provides all this windows specific networking support) | |
| 1 | smbtree | Find windows machines. |
2
| nmblookup -A 1.2.3.4 | Find the windows (netbios) name associated with ip address |
| 3 | smbclient -L windows_box | List shares on windows machine or samba server |
| 4 | mount -t smbfs -o fmask=666,guest //windows_box/share /mnt/share
| Mount a windows share |
5
| 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) | |
1
| sed 's/string1/string2/g' | Replace string1 with string2 |
| 2 | sed 's/\(.*\)1/\12/g' | Modify anystring1 to anystring2 |
| 3 | sed '/ *#/d; /^ *$/d' | Remove comments and blank lines |
4
| sed ':a; /\\$/N; s/\\\n//; ta' | Concatenate lines with trailing \ |
| 5 | sed 's/[ \t]*$//' | Remove trailing spaces from lines |
| 6 | sed 's/\([`"$\]\)/\\\1/g' | Escape shell metacharacters active within double quotes |
| 7 | seq 10 | sed "s/^/ /; s/ *\(.\{7,\}\)/\1/" | Right align numbers |
| 8 | sed -n '1000p;1000q' | Print 1000th line |
| 9 | sed -n '10,20p;20q' | Extract title from HTML web page |
| 10 | sed -n 's/.*\(.*\).*/\1/ip;T;q' | |
| 12 | sort -t. -k1,1n -k2,2n -k3,3n -k4,4n | Delete a particular line |
| 13 | echo 'Test' | tr '[:lower:]' '[:upper:]' | Sort IPV4 ip addresses |
| 14 | tr -dc '[:print:]' < /dev/urandom | Case conversion |
| 15 | history | wc -l | Count lines |
| | Set operations (Note you can export LANG=C for speed. Also these assume no duplicate lines within a file) | |
| 1 | sort file1 file2 | uniq | Union of unsorted files |
| 2 | sort file1 file2 | uniq -d | Intersection of unsorted files |
| 3 | sort file1 file1 file2 | uniq -u | Difference of unsorted files |
| 4 | sort file1 file2 | uniq -u | Symmetric Difference of unsorted files |
| 5 | join -a1 -a2 file1 file2 | Union of sorted files |
| 6 | join file1 file2 | Intersection of sorted files |
| 7 | join -v2 file1 file2 | Difference of sorted files |
| 8 | join -v1 -v2 file1 file2 | Symmetric Difference of sorted files |
| | Math | |
| 1 | echo '(1 + sqrt(5))/2' | bc -l | Quick math (Calculate φ). See also bc |
| 2 | echo 'pad=20; min=64; (100*10^6)/((pad+min)*8)' | bc | More complex (int) e.g. This shows max FastE packet rate |
| 3 | echo 'pad=20; min=64; print (100E6)/((pad+min)*8)' | python | Python handles scientific notation |
| 4 | echo 'pad=20; plot [64:1518] (100*10**6)/((pad+x)*8)' | gnuplot -persist
| Plot FastE packet rate vs packet size |
| 5 | echo 'obase=16; ibase=10; 64206' | bc | Base conversion (decimal to hexadecimal) |
| 6 | echo $((0x2dec)) | Base conversion (hex to dec) ((shell arithmetic expansion)) |
| 7 | units -t '100m/9.69s' 'miles/hour' | Unit conversion (metric to imperial) |
| 8 | units -t '500GB' 'GiB' | Unit conversion (SI to IEC prefixes) |
| 9 | units -t '1 googol' | Definition lookup |
| 10 | seq 100 | (tr '\n' +; echo 0) | bc | Add a column of numbers. |
| | Calendar
| |
| 1 | cal -3 | Display a calendar |
| 2 | cal 9 1752 | Display a calendar for a particular month year |
| 3 | date -d fri | What date is it this friday. |
| 4 | [ $(date -d "tomorrow" +%d) = "01" ] || exit | exit a script unless it's the last day of the month |
| 5 | date --date='25 Dec' +%A | What day does xmas fall on, this year |
| 6 | date --date='@2147483647' | Convert seconds since the epoch (1970-01-01 UTC) to date |
| 7 | TZ=':America/Los_Angeles' date | What time is it on West coast of US (use tzselect to find TZ) |
| 8 | echo "mail -s 'get the train'
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< /dev/null" | at 17:45 | Email reminder |
| 9 | echo "DISPLAY=$DISPLAY xmessage cooker" | at "NOW + 30 minutes" | Popup reminder |
| | CDs
| |
| 1 | gzip cdrom.iso.gz | Save copy of data cdrom |
| 2 | mkisofs -V LABEL -r dir | gzip > cdrom.iso.gz | Create cdrom image from contents of dir |
| 3 | mount -o loop cdrom.iso /mnt/dir | Mount the cdrom image at /mnt/dir (read only) |
| 4 | cdrecord -v dev=/dev/cdrom blank=fast | Clear a CDRW |
| 5 | gzip -dc cdrom.iso.gz | cdrecord -v dev=/dev/cdrom - | Burn cdrom image (use dev=ATAPI -scanbus to confirm dev) |
| 6 | cdparanoia -B | Rip audio tracks from CD to wav files in current dir |
| 7 | cdrecord -v dev=/dev/cdrom -audio *.wav | Make audio CD from all wavs in current dir (see also cdrdao) |
| 8 | oggenc --tracknum='track' track.cdda.wav -o 'track.ogg' | Make ogg file from wav file |
| | disk space | |
| 1 | ls -lSr | Show files by size, biggest last |
| 2 | du -s * | sort -k1,1rn | head | Show top disk users in current dir. |
| 3 | df -h | Show free space on mounted filesystems |
| 4 | df -i
| Show free inodes on mounted filesystems |
| 5 | fdisk -l | Show disks partitions sizes and types (run as root) |
| 6 | rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1n | List all packages by installed size (Bytes) on rpm distros
|
| 7 | dpkg-query -W -f='${Installed-Size;10}\t${Package}\n' | sort -k1,1n | List all packages by installed size (KBytes) on deb distros |
