Commands by SiegeX

Commands by SiegeX (5)

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Grep without having it show its own process in the results

The trick here is to use the brackets [ ] around any one of the characters of the grep string. This uses the fact that [?] is a character class of one letter and will be removed when parsed by the shell. This is useful when you want to parse the output of grep or use the return value in an if-statement without having its own process causing it to erroneously return TRUE. Show Sample Output
This is sample output - yours may be different.
```
$ ps aux | grep "crond"
root      2638  0.0  0.0   1912   640 ?        S     2008   0:10 /usr/sbin/crond -l10
siegex    6312  0.0  0.0   2084   636 pts/0    R+   19:42   0:00 grep crond

$ ps aux | grep "[c]rond"
root      2638  0.0  0.0   1912   640 ?        S     2008   0:10 /usr/sbin/crond -l10
```
12

ps aux | grep "[s]ome_text"

SiegeX · 2009-02-17 02:10:50 18
Recursively move folders/files and preserve their permissions and ownership perfectly
This is sample output - yours may be different.
2

cd /source/directory; tar cf - . | tar xf - -C /destination/directory

SiegeX · 2009-02-17 02:09:04 9
Use tee + process substitution to split STDOUT to multiple commands

Using process substitution, we can 'trick' tee into sending a command's STDOUT to an arbitrary number of commands. The last command (command4) in this example will get its input from the pipe. Show Sample Output
This is sample output - yours may be different.
```
$ echo foo | tee >(cat) >(cat) >(cat) | cat
foo
foo
foo
foo
```
23

some_command | tee >(command1) >(command2) >(command3) ... | command4

SiegeX · 2009-02-17 01:55:07 25
Parse a quoted .csv file

The $2, $3, $4 fields are arbitrary but note that the first field starts from $2 and the last field is $NF-1. This is due to the fact that the leading and trailing quotes are treated as field delimiters. Show Sample Output
This is sample output - yours may be different.
```
$ echo '"foo", "bar", "baz"' | awk -F'^"|", "|"$' '{ print $2,$3,$4 }'
$ foo bar baz
```
7

awk -F'^"|", "|"$' '{ print $2,$3,$4 }' file.csv

SiegeX · 2009-02-16 21:32:46 10
Convert Unix newlines to DOS newlines

The ctrl+v,ctrl+m portion represents key presses that you should do. If you do it successfully you should see a ^M character appear.
This is sample output - yours may be different.
4

sed 's/$/<ctrl+v><ctrl+m>/'

SiegeX · 2009-02-16 20:53:05 12

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Extract title from HTML files

This command can be used to extract the title defined in HTML pages

Erase a word

Go up multiple levels of directories quickly and easily.

Change to your taste. Much quicker than having to add 'cd' every time. Add it to your .bashrc or .bash_profile.

Show bandwidth use oneliner

poorman's ifstat using just sh and awk. You must change "eth0" with your interface's name.

list block devices

Shows all block devices in a tree with descruptions of what they are.

ROT13 using the tr command

grep for minus (-) sign

Use flag "--" to stop switch parsing

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Convert seconds to [DD:][HH:]MM:SS

Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

list block devices

Shows all block devices in a tree with descruptions of what they are.

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