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Created March 7, 2013 17:02
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Unix tricks
I have marked with a * those which I think are absolutely essential
Items for each section are sorted by oldest to newest. Come back soon for more!
* In bash, 'ctrl-r' searches your command history as you type
- Add "set -o vi" in your ~/.bashrc to make use the vi keybindings instead
of the Emacs ones. Takes some time to get used to, but it's fantastic!
- Input from the commandline as if it were a file by replacing
'command <' with 'command <<< "some input text"'
- '^' is a sed-like operator to replace chars from last command
'ls docs; ^docs^web^' is equal to 'ls web'. The second argument can be empty.
* '!!:n' selects the nth argument of the last command, and '!$' the last arg
'ls file1 file2 file3; cat !!:1-2' shows all files and cats only 1 and 2
- More in-line substitutions:
- 'nohup ./long_script &' to leave stuff in background even if you logout
- 'cd -' change to the previous directory you were working on
- 'ctrl-x ctrl-e' opens an editor to work with long or complex command lines
* Use traps for cleaning up bash scripts on exit
* 'shopt -s cdspell' automatically fixes your 'cd folder' spelling mistakes
- function lt() { ls -ltrsa "$@" | tail; }
- function psgrep() { ps axuf | grep -v grep | grep "$@" -i --color=auto; }
- function fname() { find . -iname "*$@*"; }
- ':set spell' activates vim spellchecker. Use ']s' and '[s' to move between
mistakes, 'zg' adds to the dictionary, 'z=' suggests correctly spelled words
- check my .vimrc and here for more
* 'htop' instead of 'top'
- 'ranger' is a nice console file manager for vi fans
- Use 'apt-file' to see which package provides that file you're missing
- 'dict' is a commandline dictionary
- Learn to use 'find' and 'locate' to look for files
- Compile your own version of 'screen' from the git sources. Most versions
have a slow scrolling on a vertical split or even no vertical split at all
* 'trash-cli' sends files to the trash instead of deleting them forever.
Be very careful with 'rm' or maybe make a wrapper to avoid deleting '*' by
accident (e.g. you want to type 'rm tmp*' but type 'rm tmp *')
- 'file' gives information about a file, as image dimensions or text encoding
- 'awk '!x[$0]++'' to check for duplicate lines
- 'echo | at midnight' starts a command at the specified time
- Pipe any command over 'column -t' to nicely align the columns
* Google 'magic sysrq' and learn how to bring you machine back from the dead
- 'diff --side-by-side fileA.txt fileB.txt | pager' to see a nice diff
* '' remembers your most used folders and is an
incredible substitute to browse directories by name instead of 'cd'
- '' is a fantastic solution to
upload by commandline via Dropbox's API if you can't use the official client
- learn to use 'pushd' to save time navigating folders ( is better though)
- if you liked the 'psgrep' alias, check 'pgrep' as it is far more powerful
* never run 'chmod o+x * -R', capitalize the X to avoid executable files. If
you want _only_ executable folders: 'find . -type d -exec chmod g+x {} \;'
- 'xargs' gets its input from a pipe and runs some command for each argument
- Don't know where to start? SMB is usually better than NFS for most cases.
'sshfs_mount' is not really stable, any network failure will be troublesome
- 'python -m SimpleHTTPServer 8080' shares all the files in the current
folder over HTTP, port 8080
- 'ssh -R 12345:localhost:22 "sleep 1000; exit"' forwards's port 12345 to your local ssh port, even if you machine
is not externally visible on the net.
Now you can 'ssh localhost -p 12345' from and you will
log into your machine.
'sleep' avoids getting kicked out from for inactivity
* Read on 'ssh-keygen' to avoid typing passwords every time you ssh
- 'socat TCP4-LISTEN:1234,fork TCP4:' forwards your port
1234 to another machine's port 22. Very useful for quick NAT redirection.
* Configure postfix to use your personal Gmail account as SMTP: Now you can send emails from the command line.
'echo "Hello, User!" | mail'
- Some tools to monitor network connections and bandwith:
'lsof -i' monitors network connections in real time
'iftop' shows bandwith usage per *connection*
'nethogs' shows the bandwith usage per *process*
* Use this trick on .ssh/config to directly access 'host2' which is on a private
network, and must be accessed by ssh-ing into 'host1' first
Host host2
ProxyCommand ssh -T host1 'nc %h %p'
HostName host2
* Pipe a compressed file over ssh to avoid creating large temporary .tgz files
'tar cz folder/ | ssh server "tar xz"' or even better, use 'rsync'
(CC) by-nc, Carles Fenollosa <>
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Last modified: jue 07 mar 2013 05:31:49 CET
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