Commands using cat (514)
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-1cat /etc/passwd | wc -l
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-1if [ -x /etc/*-release ]; then cat /etc/*-release ; else cat /etc/*-version ; fi
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I liked vaporub's suggestion, here a little simplification of the sed command.
-1MAC=$((date +'%Y%m%d%H%M%S%N'; cat /proc/interrupts) | md5sum | sed -r 's/(..)/\1:/g' | cut -d: -f 1-6) -
-1cat input.txt | sed 's/\\\033[^a-zA-Z]*.//g'
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-1while :; do cat file.txt | nc -l 80; done
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Per country GET report, based on access log. Easy to transform to unique IP Show Sample Output
-1cat /var/log/nginx/access.log | grep -oe '^[0-9.]\+' | perl -ne 'system("geoiplookup $_")' | grep -v found | grep -oe ', [A-Za-z ]\+$' | sort | uniq -c | sort -n -
-1cat .ssh/id_dsa.pub | ssh <HOST> "mkdir -p .ssh && tee -a .ssh/authorized_keys"
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Given a dump.sql file, extract table1 creation and data commands. table2 is the one following table1 in the dump file. You can also use the same idea to extract several consecutive tables.
-1cat dump.sql | sed -n -e '/Table structure for table .table1./,/Table structure for table .table2./p' -
-1cat $HISTFILE | grep command
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Or, if you have restricted access for sftp only, I think you can still do this:
diff /path/to/localfile <(scp user@host:/path/to/remotefile >(cat))-1diff /path/to/localfile <(ssh user@host cat /path/to/remotefile) -
Exactly the same effect with 3 less characters ;-) (Removes all files/filesystems of a harddisk. It removes EVERYTHING of your hard disk. Be careful when to select a device.) You can press Ctrl + C after few seconds (No output)
-1cat /dev/zero > /dev/sda -
Processes biglion quantity of sold ebay coupons/bonus codes, so you can know approximate count of users who buyed the coupons and when sales are come up again. You can change sleep parameter so script will work slowly or faster (default is 5 seconds). Additional requirements: curl Standart tools used: awk, date, cat, grep (bash) Show Sample Output
-1while true; do date; (curl -s -o 1.html http://www.biglion.ru/deals/ebay-80/ &); sleep 5; cat 1.html | grep "купонов" | awk -F"<div>" '{print $2}' | awk -F"<span>" '{print $1}'; done -
-1find . -name *.properties -exec /bin/echo {} \; -exec cat {} \; | grep -E 'listen|properties'
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-1cat "log" | grep "text to grep" | awk '{print $1}' | sort -n | uniq -c | sort -rn | head -n 100
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This is not exhaustive but after checking /etc/cron* is a good way to see if there are any other jobs any users may have set. Note: this is a repost from a comment "flatcap" made on http://www.commandlinefu.com/commands/view/3726/print-crontab-entries-for-all-the-users-that-actually-have-a-crontab#comment, for which I am grateful and I take no credit.
-1for USER in /var/spool/cron/*; do echo "--- crontab for $USER ---"; cat "$USER"; done -
Needs to be run in a battery sysfs dir, eg. /sys/class/power_supply/BAT0 on my system. Displays the battery's current charge and the rate per-second at which energy is {dis,}charging. All values are displayed as percentages of "full" charge. The first column is the current charge. The second is the rate of change averaged over the entire lifetime of the command (or since the AC cable was {un,}plugged), and the third column is the rate of change averaged over the last minute (controlled by the C=60 variable passed to awk). The sample output captures a scenario where I ran 'yes' in another terminal to max out a CPU. My battery was at 76% charge and you can see the energy drain starts to rise above 0.01% per-second as the cpu starts working and the fan kicks in etc. While idle it was more like 0.005% per-second. I tried to use this to estimate the remaining battery life/time until fully charged, but found it to be pretty useless... As my battery gets more charged it starts to charge slower, which meant the estimate was always wrong. Not sure if that's common for batteries or not. Show Sample Output
-1while cat energy_now; do sleep 1; done |awk -v F=$(cat energy_full) -v C=60 'NR==1{P=B=$1;p=100/F} {d=$1-P; if(d!=0&&d*D<=0){D=d;n=1;A[0]=B=P}; if(n>0){r=g=($1-B)/n;if(n>C){r=($1-A[n%C])/C}}; A[n++%C]=P=$1; printf "%3d %+09.5f %+09.5f\n", p*$1, p*g, p*r}' -
If you don't have telnet, you can use the bash built-in tcp pipes.
-1cat < /dev/tcp/towel.blinkenlights.nl/23 -
You could have that little benchmark run on all cores in parallel, as a multi-core benchmark or stress test First find the number of cores, then have parallel iterate over that in, well, parallel Show Sample Output
-1time cat /proc/cpuinfo |grep proc|wc -l|xargs seq|parallel -N 0 echo "2^2^20" '|' bc -
Just waste some resources in a philosophical way
-2cat /dev/zero > /dev/null & -
-2watch -n1 --differences cat /proc/meminfo
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Searches /var/log/secure for smtp connections then lists these by number of connections made and hosts.
-2cat /var/log/secure | grep smtp | awk '{print $9}' | cut -f2 -d= | sort | uniq -c | sort -n | tail -
Adds the stdout (standard output) to the beginning of logfile.txt. Change "command" to whatever command you like, such as 'ls' or 'date', etc. It does this by adding the output to a temporary file, then adding the previous contents of logfile.txt to the temp file, then copying the new contents back to the logfile.txt and removing the temp file.
-2command > tmp && cat logfile.txt >> tmp && tmp > logfile.txt && rm tmp -
-2cat /service/solr/log/main/current | tai64nlocal | grep "\(`date '+%F %H'`\|`date '+%F %H %M' | awk '{print $1" 0"$2-1":"$3}'`\)" | grep QTime | awk '{print $NF}' | awk -F\= '{ s += $2} END {print s/NR}'
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It's not a big line, and it *may not* work for everybody, I guess it depends on the detail of access_log configuration in your httpd.conf. I use it as a prerotate command for logrotate in httpd section so it executes before access_log rotation, everyday at midnight.
-2cat /var/log/httpd/access_log | grep q= | awk '{print $11}' | awk -F 'q=' '{print $2}' | sed 's/+/ /g;s/%22/"/g;s/q=//' | cut -d "&" -f 1 | mail youremail@isp.com -s "[your-site] search strings for `date`" -
Prints the type of computer you have. I think this should be used more in distros and other applications because it is so easy to get. This can also be asked by tutorials as an easy way to get your base hardware. Some alternatives:
sudo dmidecode -s system-product-nameandsudo smbios-sys-info-lite | sed -n 's/^Product Name: *\(.*\)/\1/p'Show Sample Output-2cat /sys/devices/virtual/dmi/id/board_name - ‹ First < 16 17 18 19 20 > Last ›
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