Commands tagged awk conditional (3)

  • The sample output shows each record/row with the last field zero-padded to 26 digits. For testing, I used (L)ine and field/column numbers.... Line 4, field2 = L42, etc up to the last field where I just used line numbers X 4. I had some whitespace-delimited files with variable-length records/rows (having 4 - 5 fields/columns) which required reformatting by zero-padding the last field to 26 digits. This requires setting NF (Not $NF) as an awk variable, with a simple conditional that assumes that any line where (N)umber of (F)ields does NOT equal 4 has a NF of 5. If needed, more conditional checks can be added, and the "NF" changed to any field ($1, $5, etc). Show Sample Output

    awk '{var = sprintf(NF); if (var == 4) printf "%s %s %s %026d\n" , $1,$2,$3,$4; else printf "%s %s %s %s %026d\n" , $1,$2,$3,$4,$5}' >>
    genatomics · 2014-12-20 02:53:35 8
  • Removes directories which are less than 1028KB total. This works for systems where blank directories are 4KB. If a directory contains 1 MB (1024KB) or less, it will remove the directory using a path relative to the directory where the command was initially executed (safer than some other options I found). Adjust the 1028 value for your needs. It would be helpful to test the results before proceeding with the removal. Simply run all but the last two commands to see a list of what will be removed: du | awk '{if($1<1028)print;}' | cut -d $'\t' -f 2- If you're unsure what size a blank folder is, test it like this: mkdir test; du test; rmdir test

    du | awk '{if($1<1028)print;}' | cut -d $'\t' -f 2- | tr "\n" "\0" | xargs -0 rm -rf
    i814u2 · 2015-06-25 16:00:48 11

  • 0
    awk '{if ($3 =="LAN" && $5 == "0.00" ) print $1,  $2, "LAN",  "288",  "100.00"; else print $1 ,$2, $3, $4, $5 }' sla-avail-2013-Feb > sla-avail-2013-Feb_final
    shantanuo · 2020-02-15 10:37:44 85

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Synchronize date and time with a server over ssh
Shorter, easier to remember version of cmd#7636 NTP is better, but there are situations where it can't be used. In those cases, you can do this to sync the local time to a server.

Runs previous command but replacing
Replaces the first instance of 'foo' with 'bar'. To replace all instances of 'foo' with 'bar': !!:gs/foo/bar/

Edit the last or previous command line in an editor then execute
If you would like to edit a previous command, which might be long and complicated, you can use the fc (I think it stands for fix command). Invoke fc alone will edit the last command using the default editor (specified by $FCEDIT, $EDITOR, or emacs, in that order). After you make the changes in the editor, save and exit to execute that command. The fc command is more flexible than what I have described. Please 'man bash' for more information.

Help shell find freshly installed applications (re: PATH)
Immediately after installing things into your PATH (e.g. under /usr/bin), currently open shells cannot find them ("zsh: command not found"). Use rehash to get the shell to rescan available executables.

Displays an animated hourglass for x amount of seconds

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Jump to a directory, execute a command and jump back to current dir

Rename files in batch

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"

Jump to a song in your XMMS2 playlist, based on song title/artist
Usage: Declare this function in your Shell, then use it like this: $> jumpTo foo The script will search for the 'foo' pattern in your current xmms2 playlist (artist or songname), and play the first occurence of it !

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