Commands using printf (206)

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Start a quick rsync daemon for fast copying on internal secure network
"Sample output" shows a minimalistic configuration file.

How fast is the connexion to a URL, some stats from curl

Runs previous command replacing foo by bar every time that foo appears
To replace foo by bar, but not execute, do ^foo^bar^:p To replace all foo by bar, but not execute, do ^foo^bar^:&:p

How to backup hard disk timely?
Creates files in $DATE and hardlinks existing files to $PREVDATE. Thus full backup in each directory. Only drawback is changed modification time. Recommend a wrapper script to determine $DATE and $PREVDATE. Works like a charm. (Dirvish handrolled)

A simple way to securely use passwords on the command line or in scripts
In this example, where the users gpg keyring has a password, the user will be interactively prompted for the keyring password. If the keyring has no password, same as above, sans the prompt. Suitable for cron jobs. ~/.gnupg/passwd/http-auth.gpg is the encrypted http auth password, for this particular wget use case. This approach has many use cases. example bash functions: function http_auth_pass() { gpg2 --decrypt ~/.gnupg/passwd/http-auth.gpg 2>/dev/null; } function decrypt_pass() { gpg2 --decrypt ~/.gnupg/passwd/"$1" 2>/dev/null; }

output the contents of a file removing any empty lines including lines which contain only spaces or tabs.

Exclude inserting a table from a sql import
Starting with a large MySQL dump file (*.sql) remove any lines that have inserts for the specified table. Sometimes one or two tables are very large and uneeded, eg. log tables. To exclude multiple tables you can get fancy with sed, or just run the command again on subsequently generated files.

Time Synchronisation with NTP

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" }


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