cpu usage
top
summarize size of folder:
du -sh /path/to/director
Find files changed in the last 7 days
find . -type f -mtime 7
Delete all files with a specified extention (or name for that matter)
find . -name "*.bak" -type f -delete
But use it with precaution. Run first:
find . -name "*.bak" -type f
to see exactly which files you will remove.
Find a file:
find / -type f -name <filename> # / is the top dir, ./ is the local dir
find / -type f -iname <filename*>
find / -type d -name <foldername>
find . -name <filename>
skip “type” for files and directories
locate -i "<filename*>" // example locate -i "*.txt"
might need to run updatedb
Look for a string within a file:
grep -r -i "some string" /home/yourusernamethype/foo.cpp
This will find every file with .log as extension and apply the grep command.
find . -name "*.log" | xargs grep -i 'the only string im looking for' find . -name "*.log" | xargs grep -E 'fatal|error|critical|failure|warning|'
Convert tabs to spaces in select files
find . -name '*.cpp' ! -type d -exec bash -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;
process info
px -aux
process info for specific process, for instance, an app named “hwServer”
ps -aux | grep ./hwServer
Is your vnc running?
ps -elf | grep vnc
tar-ing
tar -C /destFolder -xvf myfile.tar.gz
untar-ing
tar -xvf myfile.tar.gz tar -xjvf myfile.tar.bz2
ownwership
sudo chown brad foo.txt # changes owner of file to brad chown :brad foot.txt # changes group of a file to brad
Can’t remove a file????
Could be that the file is “immutable” – check with:
lsattr filename
If one of the attributes is “i” then it is immutable. To remove this, use
sudo chattr -i filename
then
rm filename
To copy a file from B to A while logged into B:
scp /path/to/file username@a:/path/to/destination
example:
scp /home/brad/readme.txt root@192.168.242.147:/root
To copy a file from B to A while logged into A:
scp username@b:/path/to/file /path/to/destination
Removing damaged apt-get packages-m
sudo dpkg --remove --force-remove-reinstreq name_of_pkg
creates the necessary links and cache to the most recent shared libraries…the cache is used by the run time linker.
ldconfig
************** More searches ***********
grep -rnw '/path/to/somewhere/' -e "pattern"
-r or -R is recursive,
-n is line number, and
-w stands match the whole word.
-l (lower-case L) can be added to just give the file name of matching files.
-i ignore case
Along with these, –exclude, –include, –exclude-dir or –include-dir parameters could be used for efficient searching:
This will only search through the files which have .c or .h extensions:
grep --include=*.{c,h} -rn '/path/to -m/somewhere/' -e "pattern"
This will exclude searching all the files ending with .o extension:
grep --exclude=*.o -rn '/path/to/somewhere/' -e "pattern"
Just like exclude files, it’s possible to exclude/include directories through –exclude-dir and –include-dir parameter. For example, this will exclude the dirs dir1/, dir2/ and all of them matching *.dst/:
grep --exclude-dir={dir1,dir2,*.dst} -rn '/path/to/somewhere/' -e "pattern"
NETCAT
To send udp:
nc -u ipAddr port
example
nc -u 192.168.241.207 7001
To rcve udp:
nc -ul ipAddr (optional) port
example – listens at localhost (127.0.0.1)
nc -ul 7001
example
nc -ul 192.168.241.207 7001
Note that the send command needs an IP addr, whereas receive defaults to localhost if one is not provided.
TCPDUMP
tcpdump -n src 192.168.240.100 tcpdump -n src 192.168.240.100 and port 22
can also use “dst” or neither. Can specify “port” same way
SSH
Here’s how to install openssh-server:
sudo apt-get install openssh-server openssh-client
Running a process in the background:
When you run a process, then type ctrl-Z, it *SUSPENDS* the process.
Type bg to put it in the background, then disown it to detach it from your shell.
jobs disown %1 exit
To find out which sub-directories consume how much disk size, use this command:
du -h --max-depth=1 | sort -hr
AC0ZJ 