Below some important general unix tips:
- How to run a command to a set of files (The while read command can handle names with spaces but you need to quote the variable after):
[unix]$ for i in `ls *mp3`; do cp $i $i.bak; done
[unix]$ ls *mp3 | while read i; do cp "$i" "$i with more spaces"; done
- How to rename part of a file:
[unix]$ echo filename | sed 's/file/another/'
- How to replace text in multiple files:
[unix]$ sed -e 's/oldtext/newtext/' -i file1 file2 file3 ...
- How to delete lines matching a pattern in some files:
[unix]$ sed -e '/pattern/ d' -i file1 file2 file3 ...
- How to change all letters to lowercase:
[unix]$ echo FilENamE | tr A-Z a-z
- A good way to change all filenames in a directory to lowercase:
This handles a colored ls (hence the quotes around ls, but you can use any file list output, i.e. find) and names with spaces (hence the while read and not the for).[unix]$ "ls" | while read name; do mv "$name" "`echo $name | tr A-Z a-z`"; done
- How to convert man pages to text files:
[unix]$ man man | col -b
- How to list all the open ports and programs:
[linux]$ netstat -apne --inet [freebsd]$ sockstat
- How to list all the open files and programs:
[linux]$ lsof [freebsd]$ fstat
- How to find information about an ip (i.e. 10.0.0.0):
[unix]$ host 10.0.0.0 [unix]$ dig -x 10.0.0.0
- How to find information about an ip owner (i.e. 10.0.0.0):
[unix]$ whois -h whois.arin.net 10.0.0.0
- How to find out the mailserver for an ip:
[unix]$ dig mx some.domain.name.net
- How to generate a filename with yesterdays date (i.e. for logfiles/backups):
[linux]$ touch logfile-`date -dyesterday '+%Y-%m-%d'` [freebsd]$ touch logfile-`date -v-1d '+%Y-%m-%d'`
- tail - display the end of a file
- head - display the beggining of a file
- xargs - convert stdin to command line arguments
- nmap - network scanner
- watch (linux) - run a command periodically and watch the output
- watch (freebsd) - monitor a tty
- lsof - lists the open files
- strace (linux) - trace the system calls of a program
- truss (freebsd) - trace the system calls of a program
- calc - command line calculator program
- bc - another command line calculator program
- dc - command line RPN calculator program
- du - how much disk space is being used by something
- df - disk free, how much free space there is
- touch - creates an epty file or updates the timestamp on a file
- diff - show the difference between 2 files
- strings - show the strings in a file (useful for binaries)
- file - tells you what type a file is
- finger - find out information about users
- w / who - who is currently on the machine and what are they doing
- id - tells you who you are
- uname - tells you basic information about the system.
- whois - information about hosts
- crontab - execute commands at specified times
- last - last users to log into the system
- mail - very basic mailer, useful for redirection
- nice/renice - set the niceness ("priority") level of a program
- nohup - leave a program running after logging off
- screen - virtual terminal for leaving programs running
- psnup - print multiple pages in one page
- time - time the execution of a command
- wc - word count, tells you the size in bytes, words and lines
- which / whereis - locates commands
- locate - locates files
- whatis - gives brief summary of a comm
- and
- wget / fetch - get files off the net
- talk - chat with other users on the system
- write / wall - send messages to users of the system
- zcat - cat gzipped files
- ln - link files
- sleep - wait a specified amount of time
- md5sum (linux) - calculate the md5 signature of a file
- md5 (freebsd) - calculate the md5 signature of a file
- enscript - convert text files to ps
- awk, sed - useful scripting programs
- cat, echo, more/less, find, grep - you need to know these, it's not an option.
Resource: http://sluglug.ucsc.edu/~isolis/knowledge/unix-tips/
