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|<code> free -m </code> || Free memory | |<code> free -m </code> || Free memory | ||
|- | |||
|<code> nice <cmd> </code> || Runs a command with reduced priority | |||
|} | |} | ||
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! Syntax !! Action / Description | ! Syntax !! Action / Description | ||
|- | |- | ||
|<code> ls -l </code> || List directory contents (<code>-l</code> long format) - [ | |<code> ls -l </code> || List directory contents (<code>-l</code> long format) - see [[#Terminal Colours|Terminal Colours]] | ||
|- | |- | ||
|<code> df -h </code> || Disk space summary | |<code> df -h </code> || Disk space summary | ||
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|<code> du -sh </code> || Directory space usage summary | |<code> du -sh </code> || Directory space usage summary | ||
|- | |- | ||
|<code> du -ma / | sort -nr | head -n 20 </code> || Find 20 largest files/directories | |<code> du -h --max-depth=1 </code> || Directory space usage summary of subfolders | ||
|- | |||
|<code> <nowiki> du -ma / | sort -nr | head -n 20 </nowiki></code> || Find 20 largest files/directories | |||
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|<code> pwd </code> || Present working directory | |<code> pwd </code> || Present working directory | ||
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|<code> find <folder> -mtime +14 -exec rm {} \; </code> || Remove (delete) files in folder older than 14 days | |<code> find <folder> -mtime +14 -exec rm {} \; </code> || Remove (delete) files in folder older than 14 days | ||
|- | |||
|<code> find -iname 'file*' -mtime +7 -exec rm {} \; </code> || Remove all files matching ''file*'' in current folder older than 7 days | |||
|- | |||
|<code> find -iname 'file*' -exec rm {} \; -exec sleep 1 \; </code> || Remove all files matching ''file*'' in current folder, pausing for 1 sec between deletes | |||
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|<code> chmod +x <file> </code> || Add execute permission to a file | |<code> chmod +x <file> </code> || Add execute permission to a file | ||
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|<code> lsof <folder> </code> || List open files | |<code> lsof <folder> </code> || List open files | ||
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|<code> tar czf file.tgz folder </code> || Tar contents of folder to | |<code> lsof +L1 </code> || List deleted files still held open (reported by <code>df</code> but not <code>du</code> | ||
|- | |||
|<code> tar czf file.tgz folder </code> || [[Acronyms#T|Tar]] contents of folder (or file) to an archive | |||
|- | |||
|<code> mount --bind /var/tmp tmp </code> || Create a <code>/tmp</code> mount to local <code>/var/tmp</code> directory | |||
|} | |} | ||
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|<code> diff <file1> <file2> </code> || Difference between two files | |<code> diff <file1> <file2> </code> || Difference between two files | ||
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|<code> grep <find> <file> </code> || | |<code> grep <find> <file> </code> || Show all lines with occurrences of ''find'' in ''file'' | ||
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|<code> grep -A <n> -B <m> <find> <file> </code> || As above, but additionally show the ''n'' lines after and ''m'' lines before | |||
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|<code> tail <file> </code> || Displays the last 10 lines of a file, <code>-f</code> follows any updates (eg to monitor a log file) | |<code> tail <file> </code> || Displays the last 10 lines of a file, <code>-f</code> follows any updates (eg to monitor a log file) | ||
|} | |} | ||
=== NTP / Date and Time === | |||
{|class="vwikitable" | |||
|- | |||
! Syntax !! Action / Description | |||
|- | |||
|<code> date </code> || Show the local system date and time | |||
|- | |||
|<code> date -d <string> </code> || Show/calculate the date and time represented by <code><string></code> (eg 'tomorrow', 'next week', 'thursday') | |||
|- | |||
|<code> ntpdate -p 1 -q -d ntp.domain.com </code> || Test/query an NTP server (replace <code>ntp.domain.com</code>) | |||
|- | |||
|<code> ntpdate -d ntp.domain.com </code> || Set system clock from an NTP server (replace <code>ntp.domain.com</code>) | |||
|- | |||
|<code> ntpq -p </code> || Show list of ntp daemon peers | |||
|} | |||
== System Info == | |||
{|class="vwikitable" | |||
|- | |||
! File / Command !! Description | |||
|- | |||
|<code> /etc/issue </code> || OS Name | |||
|- | |||
|<code> /proc/cpuinfo </code> || CPU(s) information - model, spec, features, etc | |||
|- | |||
|<code> lspci | egrep -i 'network|ethernet'</code> || List NICs | |||
|- | |||
|} | |||
== Terminal Colours == | |||
The colourisation of files and folders as seen through a terminal session (eg PuTTY) normally have the following meanings... | |||
{|class="vwikitable" | |||
|- | |||
! Type !! Description | |||
|- | |||
|style='background:black;color:white;font-family:courier;'| FILE || Normal file | |||
|- | |||
|style='background:#FF5555;color:white;font-family:courier;'| MISSING || Missing file | |||
|- | |||
|style='background:black;color:#5555FF;font-family:courier;'| DIR || Directory | |||
|- | |||
|style='background:black;color:#55FF55;font-family:courier;'| EXEC || Executable file | |||
|- | |||
|style='background:black;color:#55FFFF;font-family:courier;'| LINK || Symbolic link | |||
|- | |||
|style='background:#FF5555;color:white;font-family:courier;'| ORPHAN || Orphaned symbolic link | |||
|- | |||
|style='background:black;color:#FFFF55;font-family:courier;'| FIFO || Named pipe | |||
|- | |||
|style='background:black;color:#FF55FF;font-family:courier;'| SOCK || Socket | |||
|- | |||
|style='background:black;color:#FFFF55;font-family:courier;'| BLK || Block device driver | |||
|- | |||
|style='background:black;color:#FFFF55;font-family:courier;'| CHR || Character device driver | |||
|- | |||
|style='background:black;color:#FC391F;font-family:courier;'| ARC || Archive / Compressed | |||
|- | |||
|style='background:black;color:#FF55FF;font-family:courier;'| MEDIA || Media files (image, video etc) | |||
|} | |||
These colours are derived from the [http://www.ecma-international.org/publications/standards/Ecma-048.htm ISO 6429] standard for coded character sets. The above info is derived from the following sources... | |||
* http://communities.vmware.com/message/678302#678302 | |||
* http://www.wikipedia.org/wiki/ANSI_escape_code | |||
== SCP == | == SCP == | ||
In order to be able to copy files from one machine to the other... | In order to be able to copy files from one machine to the other... | ||
<code> scp user@server:/remote/server/path/file /local/server/path/ </code> | * <code> scp user@server:/remote/server/path/file /local/server/path/ </code> | ||
In order to be able to copy files within a script (and not get prompted for a user password, the public key of the machine running the script needs to be authorised on the remote server. | In order to be able to copy files within a script (and not get prompted for a user password, the public key of the machine running the script needs to be authorised on the remote server. | ||
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# If so, append the contents of the copied key to the file | # If so, append the contents of the copied key to the file | ||
# If not, copy the file | # If not, copy the file | ||
Alternatively... | |||
# On the local machine, be logged in as the same user as will be running the script | |||
# Create public key on local machine (just hit return to accept default options) | |||
#* <code> ssh-keygen -t rsa </code> | |||
# Copy key to remote machine | |||
#* <code>cat /root/.ssh/id_rsa.pub | ssh user@server "cat >> ~/.ssh/authorized_keys"</code> | |||
== VI Editor == | == VI Editor == | ||
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* '''Modify Expiry''' - To disable the password expiry policy for a account that already exists use <code> chage -M 99999 <user> </code>, to disable for all future account (ie modify the default policy) use <code> esxcfg-auth --passmaxdays=99999 </code> | * '''Modify Expiry''' - To disable the password expiry policy for a account that already exists use <code> chage -M 99999 <user> </code>, to disable for all future account (ie modify the default policy) use <code> esxcfg-auth --passmaxdays=99999 </code> | ||
[[Category: | * '''List users''' - <code>cat /etc/passwd</code> | ||
* '''List groups''' - <code>cat /etc/group</code> | |||
* '''Show group membership''' - <code>id <user> </code> | |||
* '''Add user to group''' - <code>usermod -a -G <group> <user></code> - user must already exist | |||
[[Category:Linux]] |