Display Command Output or File Contents in Column Format in Linux

When working with files containing multiple columns, data can appear cramped and difficult to read. The column command in Linux helps format text into readable columns with proper spacing and alignment, making data analysis much easier.

Sample File

Let's examine a sample CSV file with iris dataset that we'll use to demonstrate the column command ?

$ cat iris.data

The output shows cramped CSV data ?

Id,SepalLengthCm,SepalWidthCm,PetalLengthCm,PetalWidthCm,Species
1,5.1,3.5,1.4,0.2,Iris-setosa
2,4.9,3.0,1.4,0.2,Iris-setosa
3,4.7,3.2,1.3,0.2,Iris-setosa
4,4.6,3.1,1.5,0.2,Iris-setosa
5,5.0,3.6,1.4,0.2,Iris-setosa
6,5.4,3.9,1.7,0.4,Iris-setosa
7,4.6,3.4,1.4,0.3,Iris-setosa
...........
........

Using the column Command

The column command formats data into readable columns. The -t flag creates a table format, while -s specifies the delimiter character ?

$ cat iris.data | column -t -s ","

The formatted output shows clearly separated columns ?

Id  SepalLengthCm  SepalWidthCm  PetalLengthCm  PetalWidthCm  Species
1   5.1            3.5           1.4            0.2           Iris-setosa
2   4.9            3.0           1.4            0.2           Iris-setosa
3   4.7            3.2           1.3            0.2           Iris-setosa
4   4.6            3.1           1.5            0.2           Iris-setosa
5   5.0            3.6           1.4            0.2           Iris-setosa
6   5.4            3.9           1.7            0.4           Iris-setosa
7   4.6            3.4           1.4            0.3           Iris-setosa
8   5.0            3.4           1.5            0.2           Iris-setosa
9   4.4            2.9           1.4            0.2           Iris-setosa
10  4.9            3.1           1.5            0.1           Iris-setosa
11  5.4            3.7           1.5            0.2           Iris-setosa
12  4.8            3.4           1.6            0.2           Iris-setosa
13  4.8            3.0           1.4            0.1           Iris-setosa

Formatting mount Command Output

The mount command output is often difficult to read. Let's see the original unformatted output ?

$ mount

The cramped output makes it hard to distinguish mount points ?

sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=1977472k,nr_inodes=494368,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=401592k,mode=755)
/dev/sda1 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)

Applying column Formatting

Using column -t creates properly aligned columns ?

$ mount | column -t

The formatted output clearly separates filesystem, mount point, and type ?

sysfs      on  /sys                 type  sysfs      (rw,nosuid,nodev,noexec,relatime)
proc       on  /proc                type  proc       (rw,nosuid,nodev,noexec,relatime)
udev       on  /dev                 type  devtmpfs   (rw,nosuid,relatime,size=1977472k,nr_inodes=494368,mode=755)
devpts     on  /dev/pts             type  devpts     (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs      on  /run                 type  tmpfs      (rw,nosuid,noexec,relatime,size=401592k,mode=755)
/dev/sda1  on  /                    type  ext4       (rw,relatime,errors=remount-ro,data=ordered)
tmpfs      on  /dev/shm             type  tmpfs      (rw,nosuid,nodev)
tmpfs      on  /run/lock            type  tmpfs      (rw,nosuid,nodev,noexec,relatime,size=5120k)

Common Options

Conclusion

The column command transforms cramped text data into readable, properly aligned columns. Use -t for table formatting and -s to specify delimiters for CSV files.